If you're referring to 5.2, not much at all. If you're referring to 5.0 it's a massive overhaul of the Conquest map. It's about 30% wider, has a larger jungle, more camps, the camps spawn quicker and a general rebalance of XP and gold values.
The game is now more about actually fighting in lane than playing Farmville 2.0 in lane. There's generally not much to do for the support though, so it's more common to run double jungle. Mid doesn't have to AFK farm in mid anymore.
It's still hilariously imbalanced, but it's a ginormous step up from season 4.
