They wanted to bring back some of the close in, or at least personal fighting that was in the original UT. With 03/04 maps got too huge for this.
So, you'll see a return of a lot of not quite smaller maps, but maps made so that the fighting happens closer to each other, while at the same time there's still big vehicle maps.
The hoverboard is a great addition, you can't use weapons while riding it, but it gives you a lot of speed, and you can even latch on to friendly vehicles to hitch a ride. However, it has one giant drawback. If you take damage, even a single point, you'll get knocked off the board on the ground the have to get back up, leaving you vulnerable. This is a nice balance mechanic that means you won't use it to zip around combat areas, nor can someone zip in and out with the board if the flag is even remotely guarded. But, you can use it to quickly get from one fight to the next.
Despite all this, I'm more interested in the mods that'll come out for this game. I don't like deathmatch variants, which arguably all these gametypes are. Thankfully, the modding community hasn't disapointed me yet.