This was a 10-15 minutes world boss fight with tuvala gear. 

My suggestion to improve the Situation and make certain world bosses relevant again:

1. World bosses should die within 6-8 minutes independent of the time of the day, during night (dependent on region) world bosses always despawn and basicly give no loot which locks out certain groups of ppl entirely.

2. Improve the loot !

and one thing that bothered me for a long time:

something in the kutum bossfight makes the gpu go ham, has been like that for years across multiple systems.

Was just chatting about this with the guildies +1
Improve loot for sure, most people wont even move for around 500m these days.
Spawn limit 15mins instead of 30mins.

every time I go to boss there's 1 other player at most. or no one. 

I'd say just make them soloable to preserve content. at this rate there's no way to complete bosses for quests.

IMO stop having bosses spawn 2-3 at a set time.  Instead have each boss Spawn in 5 minute incriments, so if Karanda and Kzarka spawn at the same time, Kzarka spawns at 7:00PM and Karanda spawns at 7:05PM Have the bosses only stay alive for a maximum of 10 minutes.  Give them the Garmoth treatment for the HP pool, make the HP dynamic based on how many people are there to attack it.  

Biggest thing would be the 5 minute stagger spawning, This way people don't have to guess "which one dies first".

World bosses also need to drop gold bars more accurate with the current state of the game.  Just add a 0 to the end of each type of gold bar drops, instead of getting a 100k x5-10 , 1m x5-10 , 10m x5-10 , and 100m x1-4 bar drops potential, make it 1m x5-10, 10m x5-10, 100m x5-10 , and 1b x1-2 bars that can drop.  The 1b bar drops are only for the top 25 players that deal damage to the boss and the number 1 ranked spot gets 1b 2-4.  I guess thinking about it the top 10% could have a chance to drop a 1b bar. 

If mats for Kharazad and Sov. gear dropped, everyone would fight every time.

Boss loot should be relevant to all players at all times.

You guys do know that world bosses have a shared HP pool across all servers right? how fast they die or don't die during different time of the day is due to the number of players across all servers attacking it.
 

World Bosses loot isn't relevant anymore, except for Loml, which is why no one fights them anymore.

If I can make more money AFK fishing in the time it takes to kill a Boss, why should I actually play the game?

Agreed and a simple solution would be:

1. add some of the Loml loot to regular and field bosses loot tables, like Embers of the Primordial or Essence of Dawn.

2. Also overhaul the Jetina gear upgrade system. As it is now, Concentrated Boss Crystals are absolutely useless once you have completed those Jetina quests. And you can buy PEN boss gear cheaper on market, so it doesn't even make sense to complete them. So... if those Jetina boss gear upgrades weren't limited to one set, weren't as costly as they currently are (Oquilla pieces) and if they were an alternative for enhancing for boss gear at any point (instead of just TET to PEN), they'd still be relevant for making PEN boss gear for alt characters or to melt for blackstar/crafting.

A thing I noticed but is rarely adressed are the two extremely irrelevant bosses of Quint and Muraka. Whenever they spawn, you can read the despawn notification on screen afterwards, which means that they don't die anymore. These two should receive some attention as well. In my opinion, why have something in the game that is irrelevant?

And a slightly related question: are field bosses relevant in some way? If not, same question applies here: why do we have them if they are not relevant in any way?