Am agreeing it is a bit late for this kind of wide change to the economy. Also think the way he has it now is for a very specific reason. Carry weights helps make you choose what to bring rather than walking around with an armory. How crafting is now, I'm rather fine with. Moving around and doing trade rounds across the stations doesn't bother me, and helps stretch the game a little while keeping my immersion, which is important to me frankly. The world is not rolling in gear, either, so scarcity of parts seems very fitting. Also helps cut down on superpowered items making the game real easy from early on just because of equipment. Saying that though..
-Biology does need changing, you are right on this, and needs some serious love as a skill. Having it increase effectiveness of bandages (not hypos) would go towards making it not so bland. Hypos could also have varying recipe, letting different fluid/drug components go in to create a drug cocktail. Would help give the crafting of Biology a bit more use, since unless you are a psyker, most of the high lvl drugs as right now don't help you at all.
-Diassembling is a feat sink agreed, for now. Unless there are some slim chance of superior gear showing up in some stores to make taking one apart for a kickass rifle frame/etc, it's just pft for now.