I'd like to believe Team Ninja listened to all the requests for Irene Lew on twitter. So many people want to see her.
I would be happy if they did just that bring Irene Lew or Robert give him some of those combat sambo or even CQC (but then again we have leon and baymen)martial techniques. But honestly don't mind it being a brand new character and martial style that would be better than to bring old chara's like raidou or tengu which are good chara's in there own right but, something more new
I'm one of Irene's fans, and on my twitter page you can see so many requests for her that I made in the past months
https://twitter.com/Kronin1/media/grid
But before to get new characters I think that the priority should be to include the old ones; personally I would love to see all the DoA Dimensions characters missing, but if this is impossible at least Tengu should return. This tied to his popularity, higher presence in the series and uniqueness of his style compared to all the other ones (Raidou, Genra, Shiden, Kasumi Alpha).
I can't lie, if the next character is Irene I will be surely happy (I'm really fond of her despite being until now a comprimary in the DoA and NG series), but I will continue to think that something is missing from DoA5U for being considered an Ultimate version done for satisfying all the old fans: on the opposite, the presence of Tengu and the absence of Irene wouldn't give me the same feeling. In addition, for the reasons said before, Tengu and his fans really deserve to see him in the game.
Said this,if now there is a slot for only one character, I really hope that both Tengu and Irene will be playable characters in DoA6 (together with all the DoA5U cast, VF guests excluded).