That's true that in each system, the system itself is linear.  Like gathering, for instance, you gather for materials that you process into other stuff, to sell for profit.  Or killing mobs, you gradually make your way up to more lucrative spots as your gear progresses - linear.  The part about all of BDO's systems, though, that lends to a greater sense of freedom of choice in forming a gameplay loop, is the "how" in which you incorporate these systems into your own style of play.  We utilize these systems to contribute to a single overall cause, and that is earning silver.  Silver's main purpose for most players is to contribute to gear gains.

Like, me for instance, I grind mobs, PvP and enhance.  That's BDO to me.  For my friend, BDO is lifeskilling.  And for my other friend, BDO is a PVP game, mostly doing PVP stuff.  I guess the point here is the gameplay loop can vary greatly among different players, and that variance, I feel, is evidence of this game's emphasis on making the game how you want it to be, within the confines, of course.  In other MMO's, it's like everyone's doing the same thing, more or less.  DC Universe Online is a "typical run of the mill" MMO.  And in that game, everyone literally did the same thing -- quest, dungeon spam, BiS gear, mess around or play another game until the next expansion comes out.  That was my main MMO until BDO came out (fond memories).

About varying builds, though.  You do know there are "DP memes" in existence.  Players like ChaosRonin, one of the tankiest players on NA server.  In a group setting, Ronin's DP build on Mystic is a very disruptive force, I meet her in RBF and see this Mystic literally living inside a zerg of 10+ people, barely taking any damage.  Rilok, a high AP veteran Succession Ranger known for his killing potential, even speaks highly of ChaosRonin's build.  End-game players (should) also have varying builds available, Accuracy build to fight high Evasion players, AP monkey build for high DP targets, Evasion or hybrid evasion builds, etc.  Most players only have one build, though, especially newer players or those in mid-game / early-end-game stages.  I'd argue that building as a pure tank can be "reasonable", but then we're just talking semantics at that point.  Can you elaborate on what you mean by "reasonable" for me?

META builds exist in every game.  But you can build tank in BDO and have fun, if that's your thing.  Also, good luck killing a high evasion target with an AP monkey build, unsure what you mean by "reasonable" here, but I think I know what you mean.  There's a META build in each stage of the game, and the majority of players will build that way -- for PVE purposes and PVP.  But doesn't every game have META builds, like for certain classes?  I'm sure there are games that do better in the gear option department though.  IDK though, reading "there's only one reasonable way to build" kinda makes me tilt my head a bit...

I don't think BDO is "very" sandboxy, just "more" sandboxy than run of mills.  When I compare it to games like WoW or DCUO, it seems more sandboxy.  More freedom.  And no waiting around for the next expansion that will make your gaer obsolete.  Players determine what they want to do to make silver.  The price of items, aside from the pre-set min and max prices.  No PvE-Only server kinda hints to the sandboxy aspect too.  Maybe someone else can explain better, though, just throwing my 2 cents.

The fact players decide what they want to do to make silver (which leads to BiS gear), or figure out their own methods, makes me stick to this opinion.  Maybe ESO lets you do different things for BiS gear, IDK ESO, but doesn't ESO have a PVE-Only server?

The fact that it called a DP meme build should tell you this isn't a viable build in BDO. Take a DP meme build an sure it fun having 10 people hitting you and never dying but not like you can kill anyone either. So in the end of the day there really zero enjoyment out of this build once you reallize you aren't killing someone cause there a DP meme you just ignore them cause they aren't killing you either. It why it called a meme it not a viable build thus the reason why no one spams it. There literally zero serineros were this build is viable unless you just want to laugh at how piss poor the stat system is in this game. An Hybrid builds are dying out sense the only reason they worked is because you out geared people enough to still kill them, but in an equal footing ya you'll feel tanker but you'll also just struggle to kill others so is it really a build? It basically just a weaker version of a DP meme with a bit more damage in the end. An on top of that PVE wise the only build that matters is stacking AP sense it the #1 thing that locks you out of PVE content so you can't play a DP meme killing mobs unless you just like getting shit trash per hour rates.

Thus progression in this game is completely linear and actually more retrictive than game's like WOW, DCUO, and ESO. Infact ESO has far more sandbox elements in every aspect of the game compared to BDO especially in regards to build diversity. An to answer this question "doesn't ESO have a PVE-Only server?" ESO a PVE game with two different PVP game modes so no it doesn't have PVE deicated servers it just a PVE game.

Well this is due to the core combat system is garbage from the very root.

This is their first mmo, so that ain't really a wonder here. They didn't had the knowdolage and competence of that of wow's early developers and they didn't even took the effort to check how other games work. The current DR substract the attacker's AP is a rather budget combat system, and is doing it's jobb poorly. The pointless bracket system ain't make the things better either, neither the lack of secondary stats.

Althrough it's unlikely that they ever change it, that would be too much effort and would shake up things a lot.

It is not an option for end game gear in those games.  You group or don't get end game gear. 

Just gonna touch on one point here:

"The fact that it called a DP meme build should tell you this isn't a viable build in BDO. Take a DP meme build an sure it fun having 10 people hitting you and never dying but not like you can kill anyone either. So in the end of the day there really zero enjoyment out of this build once you reallize you aren't killing someone cause there a DP meme you just ignore them cause they aren't killing you either."

I dare you to tell ChaosRonin her build isn't viable or enjoyable.   It is correct that a DP build will not kill.  But then it boils down to context.  It may not be a viable build for spot defense in solo rotations, but in a group PVP setting, I can tell you first hand playing DP is effective member of many team compositions.

It also boils down to personal interest.  Yes, "you" may not enjoy it, but I'd hope you know you don't speak for everyone else, like you're doing here.  I've played a DP Mystic build back in the day and played against DP "memes", and LMK tell you, it's no meme at all.  It's just what the community coined the term "DP/tank build" as "DP meme", because no one really does it because most players benefit the most from cookie cutter builds.  This doesn't apply to everyone though, look to ChaosRonin as an example, as well as pretty much every geared Shai main who PVP's.  And in my first hand experience, it is quite enjoyable.

EDIT: I get what you guys are saying.  That for the majority of players and situations, a cookie cutter build is the most viable.  And I agree.  Most players do not have the silver to have multiple builds, to start off with and in most scenarios, a cookie cutter build, or something closer, is best.  DP builds are not viable for grinding either, since you want to kill mobs as efficiently as possible. 

Where DP builds do lend their viability, though, IMO, is in a group PVP setting and if that player enjoys the tanky playstyle.  So I guess I somewhat agree with what you guys are saying, but not completely (about builds in BDO).  Other games do better in the gearing department though.  IDK, in BDO, in all it's solo-player-money-per-hour glory, it's AP, AP, AP, AP and a bit of Accuracy sprinkled in, I'm sure there's much more improvement that can be done in this department.  My goal for 2021 is to reach 297 AP (pref 301) wearing Kutum with an Accuracy necklace or belt (not sure which one yet) along with a TET AP and Evasion necklace or belt. Choosing one or the other depending on the situation.  I have accuracy and evasion off-hands at PEN, but they hurt AP a lot and lots of players are going DR now, so ehhh...need moar AP, so I'm going for this goal ATM.

Enough of this...

I put 17,500 hours myself into this game, most of that,  NOT away from keyboard other than horse training. And the only TETs I've been able to RNG my way to was my Staff & Awakening.   I watched dozens of people in former Guilds I was in, get TETs way before me because they had normal "Luck" while BUYING MORE attempts a lot faster than I could (ArtisansMems) while the only thing I could do was pile up more resources 

...and big "Stacks" when everything kept failing.... 

Stacks...I still can't USE simply because the RNG refuses to let it "happen".   So don't just project onto everyone else how EASY it was for you.  That's the most NON-helpful thing that can be done here, and actually has the reverse effect of making some of us Double down on avoiding the enchanting process entirely while becoming more bitter.   I might have even gotten more TETs by now if my experiences on the forums in every one of these discussions that came up were anything but "LOL just get good at being Lucky, plebs". 

...And then total Dirt Bags who say that never explained the process or the "tricks" they used to get almost every TET they own between 50 and 80 stacks!  ...So here I am, doing everything thing there is still to do in this game EXCEPT for enhancing.

Well, I do get your point, I guess? But still, the situation you've described only really applies to the upper 1‰ of the playerbase and even in that 1‰ probably just to certain classes. I can't imagine that such a DP-build would be viable for classes without strong defensive passives (and you have to admit that Mystic/Striker really, really, really profit from their passives). I do however accept Shai as reasonable example since Shai can be played as dedicated healer - sad though that that role still only is viable in very niche scenarios.