Actually, the music in the DX3 Trailer sounded just like the intro to the Original DX Theme before it kicks into action.
As long as they let the game don't run like crap, they bring back the PC-style interface, and ditch the stupid unified ammo thing (instead for DX3, we should go back to what the original DX had w/ each weapon has its own ammo like most games do, I think we'll probably be okay -- despite those uncalled for stupidities in Invisible War, the game and story itself was still great. They just messed up the technical aspects and the gameplay aspects of DX: IW, namely. The upgrading of your character via the biomods was great in DX: IW -- just expand on that majorly in DX3 and we'll be happy, there. Also, as long as DX3 keeps the "decision-making" elements for siding w/ factions, performing missions/tasks, we'll be fine.
W/ no Ion Storm and no Warren Spector present (who made the original DX), that might hurt a bit. Then again, maybe this what the game needs -- a new team to bring new flavor and life to the series. We know that w/out Harvey Smith (the lead for DX: IW, who made a lot of the design choices for IW), DX3 is already headed in the right direction. We'll just have to wait and see how this pans out.
Let's hope DX3 will be the revival of the DX series. I'm hoping it will be. Only time will tell.