There are literally dozens of possibilities to give Ventus more depth and weave an interesting backstory without having to go so much over the top and include a totally different era and yet more convenient memory loss and possible identity problems. How original, like that wasn't used a hundred times before in this series.
DDD already played that ball with Xehanort knowing so much more than anyone else and becoming insufferably near-omniscient that I wouldn't put it past Nomura to play that in this case again as well.
Yea, if the story is put on hiatus for a year it is no wonder that Ven only had a few lines so far and those didn't actually improve on his backstory nor his characterization yet. The only thing we know so far about Ux-Ven that is different from BBS-Ven is that he is much more timid and shy, which may also come from the fact that he's significantly younger in Ux (about 10/11).
Otherwise, as shown by the few comments made by Skuld, Lauriam and Ephemer about or towards Ven he is personality-wise exactly the same as Xehanort describes him in his BBS reports (too benign for his own good, which is taken up by Blaine somewhat) and as we know him, kind, friendly etc.
As things stand right now he becomes even more of a plot device rather than an actual character. A "prize" from the past for Xehanort, possibly Marluxia/Lauriam and Sora & co. to have a tug-war over.