I am a way too tired, and there's a tad bit too much server-lag today for me to really dig in already, but I can already say that these maps are a huge step up from their BF3 ancestry. I've not yet played Metro, but Caspian and Oman are flippin' amazing, and even Firestorm - which I loathed in BF3 - has gained a lot of personality.
The sandstorm on Oman must be the most impressive videogame wheather to date, and Caspian is just flat-out amazing, with its new Levolution-element at the central capture point (which has now a whole undergournd lair coming with it, as well as a secret entrance) - and damn if that borderwall isn't crazy iconic.
Apparently a team at EA/Visceral was responsible for the overhaul of these maps. Likely the guys who are doing the rumored Police-themed Battlefield game. These maps certainly make me hopeful that I'll enjoy their efforts in the future. Bring it on!