Footkerchief, as always, the voice of reason and reasonableness.
Aquillion, the two main points we all seem to be going back and forth on are FPS and whether extra dwarf-work should be put into the game.
I don't think your FPS argument has any merit to it. Even a huge space increase would have negligible effect, when you compare day-to-day mining projects. As Foot points out, requiring a greater farm taskforce simply means fewer idling dwarves, except in a very few specialist cases where you have your whole population doing something, in which case either (a) there are already FPS issues to consider carefully because you're doing some sort of megaproject, or (b) you have a tiny fortress, so no idlers, so your FPS isn't going to take a hit anyway.
"Whether extra dwarf-work should be put into the game", for the sake of reality or fun or difficulty or what-have-you in farming, is something you seem to be arguing about in general, and because it's a matter of taste, there isn't going to be any consensus here.
However, I'd put it to you: since you don't think farming should change in any of these suggested ways, is it the case that you want to see balance much later on, as you suggested, even though it means the game is pretty badly broken at the moment? How much required balance can we defer indefinitely? (You said 'post-magic-arc', which is about as indefinite as it comes). Do you really want to see farming
abstracted offsite
?
You've suggested that with a new system, we'd find farming an initial challenge but eventually get to learn it, and it would cease to interest. This is a persuasive idea, but you don't take into account solutions such as occasional disasters (RNG or emergent - pestilence, blight, swarms of locusts), or a farm system that continually scales in difficulty with the fortress, or much less abstract plants which would require the player to work out how to change their modus operandi to suit the specific local biomes/climate. What say you to things like these?