Yep, could be B4... I hope they don't though or have both. It could be a really interesting story linking up all the 'ex-Borg', dealing with the galactic fall out of the 'end' of the Borg seen in Voyager (as if! ) and maybe a story of redemption/rehabilitation/revenge for Lore?
That is is Data or B4.. seems to obvious and some classic trailer misdirection?
I agree that there's likely more to the Data thing than we're seeing, and Lore is a good call (though I honestly never cared for the character), but I would be more than happy if, whatever they do, the net effect is to roll back the horror of Nemesis. And I really wouldn't mind if they find a way to ditch the emotion chip while they're at it. The movies weren't kind to Data (even if the rot had its roots in Descent).
Overall my feelings are mixed on this trailer - there're moments which feel like they will be nice calllbacks to TNG at its most thoughtful, but it's mixed in with the kind of Big Portentous SF Kung-Fu Action that I was hoping a Picard-centred series might be a nice contrast to.
Kung Fu Picard is sadly the direction the actor wanted Picard to go in as the movies went on. I like a bit of action Picard but I also like to think Picard is about more than just action and that's where his true presence and power are.