Special (I leave it up to the devs to determine what is special) forms and techs I have 0 issues with being quested for, rare dropped, or purchased after doing a quest like on Eilen. I firmly believe, though that all normal forms and techs from T1-T5 should be purchaseable with either coin, bounty markers, or lore tokens. Special quests to gain access to the merchants would be perfectly acceptable.
Remove bounty markers from drops, rescale tech purchase costs up to T5 and create bounty marker rewards as an option to the current xp/coin rewards on trophies. It doesn't have to be as elaborate as the 5 level tierings for xp/coin. Just make all T1 trophies worth 1 marker, T2 worth 2, T3 worth 3, etc. The number of tropies currently dropped might have to be cut back a bit, as some common mobs appear to have 3-4 loot slots and few items to fill them with already.
Set up an exchange rate and NPC for bounty markers <--> lore tokens and tack on an exchange surcharge.
These changes give multiple paths to acquiring techs and forms and takes a large chunk of items off the loot tables, hundreds of individual formulas and techs sitting in hundreds of guild halls can be replaced by a few stacks of IBMs and/or tokens, and much less annoying form spam for pure adventurers.
Another option I would support would be to only make up to T4 purchaseable and add T5 to chests; not necessarlily Labyrinth chests, but overland spawn chests as well when/if they are added.
Drev