In my opinion, Stars Wars didn't need a sequel... the ending of Star Wars Six was good enough, and there was nothing hinting at the fact there would be 'future evils', and a sequel coming out after so long just feels out of place. The evil person in the trailer will probably turn out to be some Sith badass, especially seeing Lightsaber duels are becoming more and more... better, as the series progresses.
The damn T-shaped Lightsaber just ruins everything. Based upon how swords go, you'd be THINKING the weapon would at least give it some strategical advantage, which is might, but from the way I see it, the only way you're getting anything out of that is by... maybe, MAYBE getting close enough to your opponent to sorta just 'sideways slash' them. Not only would that be a complete waste of your time, because if you have the opportunity to do THAT, you just might as well go for your basic Lightsaber slash with the longer blade, but they would probably lose their arm in the process, and maybe their head (because whoever they're duelling will totally sit there and let them awkwardly slash them with their little cross handle).
It could be used as defensive purposes, but really, this weapon would do way more hurt then it would help. Chances are, we're just going to be met with a scene at the end of the movie whereas this new villain person 'accidentally' hurts itself with its own weapon, and ends up killing itself, in a 'comedic Disney ending lolololol'.