I made a really nice post and then accidentally hit back on my browser
1) I would stop cooking by not making kitchens. Just like I don't make dyer's workshops. The cost to eating raw food is a small unhappy thought. The benefit to eating raw food is decreased preparation time, increased fortress space from no kitchen (or pot), and overall simplicity of the fortress.
And I want to emphasize this, because I feel like I've been going around in circles: happiness, as it stands, is insufficient reason to cook food for many of us.
2) Changing the space requirements of raw food does nothing to change the relative value of cooking to not cooking. If my raw plump helmet stockpiles take up half the space they used to, there is still no benefit to stockpile space from cooking.
3) I was mistaken regarding skill quality and communal cooking. I generally make a dedicated cook and turn off all other labors on him until things are cooked. That wouldn't be possible, or rather, would leave him idle frequently, under your proposed changes. So skill progresses slower, time-wise. But the quality of the 1000th prepared meal is the same either way. (It would be kind of a hassle to find make-work for my cook, but I could live with it.)
4) I have had a hard time understanding parts of your proposals. I'm going to describe how I currently describe it. I am going to be very specific, more specific than my understanding warrants, because it sounds like you want to know how to make things more clear.
When a dwarf gets hungry, he will check for the presence of prepared food. If there is no prepared food, he will try to cook food. If he can't cook food, maybe because of no pathable kitchen, he will eat raw food. He will do this regardless of whether cooking is enabled on his labors. Only after cooking (if possible) will he eat.
There will be a new kind of building which we'll call a pot. When a built pot is empty, it will generate a cooking job at a kitchen. This job will only be accepted by a dwarf with cooking enabled. Once cooked, the food will be moved into a pot.
There will be no option to manually (through the manager or through the workshop) create cooking tasks. If you want a cooking task, place an empty pot someplace.
Prepared food will disappear from stockpile settings. Prepared food that is not in a kitchen or pot will rot. Prepared food will not be able to be brought to a depot, or else it will rot quickly enough that there's no point to doing so.
How accurate is that? (I translated a lot of things like "Dwarfs should do this" into exactly how they will behave-- I think that sort of thing is necessary to really evaluate proposals like this, because the devil is in the details-- or rather, it's easy to miss exactly how things play out unless you spell out the details. For instance, after writing this, I wonder: well, why not just make a stockpile of pots to store tons of prepared meals?)
Now, like I said, my problem with this is that I don't see a point to bothering with prepared meals under your system. To be useful, cooking needs to solve a problem. Here are some potential problems:
1) Gives dwarfs significant bad thoughts for eating raw foods.
As has been said, if you do this, you need to make other changes to happiness as well. You don't want to screw up beginning fortresses.
2) Require diversity in diet for health, which is easiest to provide through prepared foods.
You've said you don't like this idea.
There's something else I see on review, which may be what you originally intended:
Kitchens are necessary in order to preserve food. Once you have a kitchen, dwarfs will insist on using it to cook their food, whether you like it or not. So the problem solved by cooking is rot, but prepared meals (and the labor they require) are an unavoidable cost of kitchens, rather than a function served by kitchens.
I know I've been wordy, especially considering losing my earlier essay
That's because I think that you and I probably play very differently. I think it's important to see how a wide diversity of players would see these changes. I represent a faction that would, for instance, see food preparation, in the absence of all current functions of cooking except happiness, as a net loss to my fortress. It feels like you don't believe me when I say that. Do you see how I could feel that cooking wasn't worth the benefit?