Aquifers are still visible on the embark map, farming hasn't really changed.
One annoyance I've run into is the new hauling mechanics, dwarves will now bring a bin/barrel from the stockpile to collect the item rather than the other way around, this sounds great in theory, but in practice they make your entire supply of plump helmets unavailable as they march them off to your farm to grab the one newly grown stack causing your brewer to throw a fit and cancel his drink making. This can be avoided by having a no-container stockpile feeding your main stockpile and having your main stockpile only take from that, but it's really annoying and I don't think it added much.
In that same vein dwarves are now much more easily overloaded when hauling then they were before (Or at least they seem to be) which makes having wheelbarrows or minecarts a big plus when possible, I personally like this change as it makes me think a lot more about how I set up my forts.
When mining stone and ore they seem to drop at about a 1/5th of the rate with a legendary miner, but when smelting you get additional bars per ore (4 I think) and when making stone blocks you get additional blocks (4 again). This makes blocks a much more attractive route for building materials especially if you didn't have a lot of stone to begin with.
That's all I can think of for the non-spoilery changes, there's probably other stuff I'm not thinking of though.