To strengthen alchemy, it would make sense to remove all mob potion drops (including towers). As mentioned here and there by different people, obtaining certain potions like PoP and majority of combat potions is too easy via mob drops. Being forced to buy the potions instead from alchemers would strengthen the position of now so redundant alchemy skill.
If people are very keen on their potion drops in towers, it could be changed so that the potions would be destroyed upon dying/leaving towers. The influx of mass cheap combat potions from towers and insanely low chance of alchemy success render them pointless to attempt to make.
Potions in normal mobs aren't a usual drop, so I don't think there's need to delete those. PoPs also go for 100k~ The thing I like about the suggestion is the potion destruction after dying in towers. +1