Alchemy builds are perfectly viable-certain potions, mutagens, and bombs can turn you into a powerhouse. I think it works just fine. You just don't get the really overpowered potions unless you go into alchemy, so it won't play a prominent role unless you want it too. TW1 was never a difficult game, and some of the potions you got access to made it even easier. That's not necessarily a bad thing, but I understand the reason it was balanced this way.