One of the reasons I decline most DFSs and swap servers, while also avoid BA and RBF is that Draughts, Elixirs, and Perfumes all disappear upon death.

Right now players that have billions of silver to spare on Perfumes and Draughts have a massive advantage.  In a 20 minute RBF, you die on average once a minute.  Since a SPirit perfume is 1.25m and Giant Draughts are 1.0m you can easily spend 135m an hour in RBF while getting a max of 30m from rewards.  In Battle Arena you can easily die every 15 seconds while winning half the fights costing 540m an hour just to practice.  IF you use Perfumes of Courage, charm, Khalks', Armor Draught, or Elixir of Deep Sea, The price goes up into the billions for a proper practice session.

Suggestion.  RBF/BA/Duel deaths no longer clear elixirs/Draughts/Perfumes. 

Better Suggestion, all PvP Deaths no longer remove Elixirs/Draughts/Perfumes

Even better, make them PvE only/delete them in RBF/BA, so ppl not need to waste rescources/time on getting two line of buffs for PvP...

2 Solid suggestions.

Even better than the other 2 suggestions.  PvP Cron should have +5 crit and +5 Attack/Cast speed.  Make the "bonus" damage and +AP from Draughts/perfumes no longer apply to PvP, so that if people REALLY want to use those expensive items they only get + max stamina, +MP on hit, +Max HP, and +HP on hit which is still an "advantage" but not as big of one.

I'd be happy with: 
make Corrupt Oil of Immortality far more readily available

Drastically reduce the materials required to craft it, add/increase the proc chance of mastery to produce more of it  

I used a bunch of [Event]Corrupt Oil of Immortality on Giant's Draughts in RBF yesterday and loved having the extra damage the whole time.   
But this is unsustainable, the oils are far too rare & tedious to acquire.  

If the Corrupt Oil of Immortality was significantly cheaper (and more profitable to craft) then: 
1 - we'd have more alchemists making it, 1 step closer to making alchemy more compelling choice of gameplay

2 - we'd have more people using Giant's Draughts every 15 minutes even for RBFs because they wouldn't lose it on death, creating more demand for Giant's Draughts  

3 - I'd personally have more fun because I liked having a Draught that didn't go away on death for a whole RBF, I just don't wanna pay close to 10m for the privilege

The Remnants of Burnt Spirits, need to be craftable from Delotia and Turo Hearts need to be listable on the Central Market so Alchemists don't have to grind turos just to make them.  A far simpler solution would be to remove the stupid "on death" mechanic.

Removing on-death is simpler, 
but BDO always seemed to me to be a game with a complicated interconnected economy, so I like solutions that involve the intersection of multiple craftings/lifeskills.   

I mean if they remove the death penalty for draughts and other consumables, they might as well delete corrupt oil of immortality from market and everyone's inventories, too. 

Rather than delete them, make them able to be sold to a vendor for 10m silver so people can get their silver back for the items they created.