Healing potions in 4th Edition suck.
These are supposed to be the iconic consumable item. They're cheap, they're ubiquitous, and they're always useful. They're a cure light wounds in a bottle. No adventurer should go without.
By contrast, in 4th Edition, drinking a healing potion uses up one of your healing surges, and instead of your surge value you heal 10 HP. You can drink a potion as a minor action.
Now, that's not useless. Up until about level 5, 10 HP is probably more than your surge value. And healing as a minor action is otherwise something that only clerics, paladins and dwarves could do. But it uses up one of your precious surges. It's just not as good as you'd expect a one-shot magic item to be.
The first thing that confuses about healing potions is that they're flat rate. Every other healing effect in the game does proportional healing, based on the 25% surge value. Heal pots give you a straight-up ten.
There's two arguments behind this that I can see. One is an intention to keep healing potions as a low-level item. They're really only useful during the first half of the heroic tier; after that you'll need to find more powerful potions that presumably cost more gold. If healing potions scaled with surge value, you'd have to artificially scale their cost to match, or high-end adventurers would be forever carrying as many as they could haul.
The other aspect of the flat rate is that it benefits low HP characters more than tanks. 10HP is practically two surges to a wizard, while it's only just above a single for a fighter. The potion is therefore proportionately more valuable to the wizard. Flat rate healing for potions (and only potions) casts potions as a "wizard item", providing a bit of flavour both to the item and the class.
Now, why does the potion use a healing surge? It's a magic item - isn't it supposed to be a bit special? Other "super-heals" like cure light wounds are able to heal players without consuming surges.
Presumably this is for balance reasons. While low-level characters certainly benefit most from these potions, there's really nothing to stop high-end characters buying them in bulk and chugging one on each and every minor action. 10HP might not be earth-shaking but it's nothing to sneeze at when it's happening every turn.
Balanced it may be, but it's not fun. When you acquire a magic item, it's supposed to feel like you're beating the system in some way. A healing potion is the RPG equivalent of having an extra life; it's a special, unique commodity. 4th Edition relegates them to just another everyday heal.
Suggestion: make healing potions not consume a healing surge, but rule instead that players can only drink one potion of any sort per extended rest. (Or once per milestone, if you feel generous.)