They are definitely useful (re: stat potions). My point is that they aren't useful enough to have a balanced demand for the supply levels we see in game. This is even more true of restorative and ward potions. If some guy just got 5 mega pots of vit from a timeworn chest, why should he buy them from me on the AH? Because mine are HQ? If he's not using them regularly anyways (due to vicious cooldowns) and clearing content, then why does he need HQ?

If square does anything, it needs to be related to lowering the supply side of the chain. They can do it by removing universal potion cooldowns, increasing the effectiveness, shortening the universal cooldown, removing consumables from coffers, or a combination of these. These will either increase demand, or shorten the supply, either of which would increase the need for alchemists.