I would say, make the health Potions as rare-items, don't put the potions into the Vendors and let the Player as before make use of them at Boss-fights.
Why would you take them slowly out of the Game, THEY ARE CULT-items, they MUST have to be in every Diablo Game!!! I'll see it on WoW, the Health-Potions can't be use at twice infight, Many people don't use them and it su**s. Near every RPG or MMORPG has got potions, only Blizzard.
Maybe this function brings more slots into the bags, but why do we have got the Belt... The only problem on Diablo 2 was, that you become too much and to easy Health-Potions. Make them not easy to farm and it would be great, nut don't take them out!!!