I like that they don't show the Empire as being old news, as the end of "Return of the Jedi", especially the special edition, implied that it fell instantly following the death of the Emperor.
I could actually see the crossguard working well, depending on the wielder's fighting style. Something more straightforward and (for lack of a better term) European would be able to make good use of it, as opposed to the spinning, fancy styles used in earlier movies, which were based mainly on kendo (for the original trilogy) and tai chi (for the sequels).
Someone posted an article about how another's lightsaber would probably cut instantly through the crossguard's projectors, which I think is an unfounded assumption. Although the "official" line is now that the existing expanded universe is non-canon/an alternate continuity, Lucas and co. haven't been shy about mining it for material before. The capital world of Coruscant was introduced in the expanded universe, after all, and didn't become officially part of the movie continuity until Episode 1. Similarly, the expanded universe introduced several minerals and metals that were resistant to lightsabers...not completely immune, but tough enough that even Jedi had to put in time and effort to carve through them. Why all lighsaber hilts wouldn't be made of similar materials is speculative, but likely due to the metals' rarity.
All in all, this teaser makes me hopeful, but not jizz-my-pants ecstatic.