I'm playing Dynasty Warriors: Gundam Reborn too and it is hella fun.
The maps are back to being one big field which is good but they are noticeably smaller than 2's which is slightly disappointing but still better than 3's pathetic excuse for maps.
They've expanded on the SEED's cast a little too much for my tastes, having to see those stupid druggies every second mission gets tiring quite quickly but I suppose it does provide some variety from seeing the Black Tri-Stars or Yazan's team like in the older games. Cagalli being playable is nice though, I didn't even know I wanted that.
SEED Destiny's story was terrible too, if you're going to make me go through that [parasitic bomb] the least you could do is let me play as, you know, Shinn? Not [tornado fang]ing Kira and Athrun. I want to defeat them not be them. As a whole though the Official Mode is pretty underwhelming.