it would certainly make sense. Personally, I'd love being able to craft or cook pumpkin soup. Speaking of which, it'd be interesting to see certain food items give temporary buffs or debuffs as well, like the rotten flesh for example. Pumpkin Soup could give the Power 1 effect for 1 minute, for example.
I'm sort of indifferent about it. Yes, pumpkin is edible in the read world when prepared as part of a recipe. I can see it used the same way in-game, as part of a recipe rather than something to munch on raw. Pumpkin pie is the obvious choice. But I'm not losing sleep over its lack.
They should make the pumpkins you harvest completely normal ones (no face carved into it) and when you use it in a recipe, a hollow pumpkin stays (just like an empty bucket when you make cake) which is identical to the current pumpkin (which you can craft into a jack o lantern)
Pumpkin soup would be nice! But as fossilized said, not losing sleep over it, either.
I think a hilarious use for pumpkins would be like saddles for pigs: You could put it on a mob and they'd wear it like a hat, like Snow Golems already do. I would also like food from pumpkins, but it would always be humorous to look outside your window and see a cow with a pumpkin as it's face. And on these same lines, using a Jack-O-Laturn would make it light up, too.
I think the uses we have for pumpkins are enough and I think that we have enough food items already.
Pumpkins are mostly used for decoration, but you can also make snow golems, iron golems, light your way in caves if you don't want to use torches or glowstone, wear them on your head to make things harder for you when you are fighting mobs (except for the endermen).