I see some people complaining that making farming difficult would make the game tedious and unfun, however I believe the troubles and difficulties of farming (enormous fields, irrigation, pest control, fertilization, weather conditions, and an otherwise useless caste of peasants to do it all) could be put in the game and make it no more tedious than it already is.
Now bear in mind I didn't bother to read most of the thread so sorry if any of this has already been said and that I am not talking about this as if it was something to work on now and implement soon but more as something that would be good to see in the distant future when we have wheelbarrows, a better interface, and lots of automation.
Now with this suggestion I think that a lot of people believe we would have to make enormous farms in every fortress (to prevent early starvation) and that it would be made square by square, farmer by farmer as it is now. However, I think how it should be is how it is in reality: instead of every fortress being an agrarian center, many sites dedicated to farming (and nothing else) would be created by civilizations in world-gen and by the time the player starts playing all the agricultural infrastructure would already exist in the world and the player would merely have to create a trade agreement that would send caravans of food to their fortress.
My idea is that the player wouldn't have to do any farming if they didn't want to, and if on the other hand you might find the idea of running an agricultural fortress an interesting challenge to try you could do it and deal with the many obstacles of farming. Also if you were a farming fortress caravans would come to trade goods for your food instead of vice-versa.
Another great thing in addition to making farming a choice rather than a necessity, is that it would add meaning and goals to the game as civilizations will have an actual reason to expand and claim large amounts of land, you would have trade routes that actually matter, sieges would become an actual danger, and the underground river would become a treasured resource.
And each civilization will farm differently: humans will make above ground fields, elves will probably have orchards, goblins will farm livestock, and dwarves will farm underground. Although, farming underground doesn't make much sense realistically as it combines all the problems of farming with all the troubles of mining but, it would probably be safer when it comes to war thus averting the need for a large warrior caste to defend it and making dwarves a post-feudal civilization.
Lastly, if the amount of land needed is too much despite the low population of the DF worlds (compared to reality where even a small country has hundreds of thousands of people in it) then the time crops need to grow could be kept lower than it really is to allow for a bigger harvest.
Also I would like to remind everyone who read this far that this is a suggestion for the distant future where transportation is improved, dwarves have lots of automation in their lives, fields can be designated as large as you want, caravans are better implemented, and the game is generally prepared for this sort of thing. I just wanted to show how this could work without making the game less fun, if it is to happen.
Sorry if I rambled too much, I have a tendency to lose my train of thought...
I hope that all made sense and explained what I was thinking.