I agree that food from farming is too easy. But, especially for newbies, it's also too
hard (or at least has too many non-intuitive pitfalls).
My proposals are to:
1) Give removing food from the kitchen highest priority and don't let a kitchen become cluttered except in extreme cases. Basically, if any dwarf is on food-hauling in your fort at all, you should never have food rot in the kitchen.
2) Make growing skill slightly less important in determining crop yield; a max of 4 crops from an unfertilized square is reasonable. Retain the current max limit from a fertilized square (so fertilization becomes more interesting).
3) Have all processing create 3 instead of 5 units from each input. One plump helmet gets you 3 dwarven wine; one cave wheat gets you 3 flour; one quarry bush gets you 3 leaves.
4a) possibly restore the 2D version's requirement that an underground field be irrigated before planting, but not without giving dwarves a way to melt water and also providing more sources of underground water, even under non-mountain areas (and letting some hint of them show up on the location map). Find a way to make 1/7 spots of water disappear rapidly when a pool is deliberately drained.
4b) Alternatively, let dwarves manually wet, churn up, and fertilize a floor, turning it into permanent soil that dries out every winter; the wetting will need to be done by bucket from a water source at least every year. Setting up the field should require a great deal of labor, but should be able to be done almost anywhere. Re-wetting or wetting a soil layer should take little effort. Have the dwarves request buckets if they aren't available.
5) Forbid the cooking of booze and seeds, unless the item type is especially marked in the raws.
6) Give serious consideration to restoring the 2D version's prohibition on winter crops. That perilous ~110-day stretch between the last fall and the first spring harvest made food management a lot more interesting, established a compelling natural cycle and thus a genuine medieval feel to the game, and gave a tremendous impetus to story-telling.
7) Let immigrants be delayed until there's at least some food available (allow food crises and shortages, but don't dump 20 dwarves into a place without even food for the original seven). The combination of large early spring migrations and fallow winter was a tad harsh in the 2D version.
8a) Include a step-by-step plump helmet "how-to" in the manual, or
8b) Use the wiki as a substitute for a tutorial. If a game is started and both "NEWBIE:YES" is on in the init and no previous game was played, bring up a message pointing players to the wiki, preferably to the page on food, which is (and will likely remain) here.