I'm definitly glad you are able to access the voices from the Next-Gen MUA2 because that was something Tomato or I had no access to or were able to figure out a way inside of the game discs once we got a hold of one. I don't even remember what exclusive characters were made available to play on the PS3 or XBOX360 versions. 
That would be Iron Fist. Juggernaut is not included in the Next Gen versions unless you've got some kind of code, and his lines are missing in my copy. Anyway, John Di Maggio reprised his role once again, so it would only serve as an expansion pack for my previous release.
There are plenty of old characters with new voices. From Cap to Jean, passing through Thor and Reed Richards. In my opinion, Vicarious Visions did an inferior work in terms of voice acting, especially when Raven did such a great job in that aspect. But it's still decent, and the geek in me is already trying to match those different voices with other characters. I'm just thinking out loud, but for example, this new Jean Grey could be Rachel Summers.
Then, there's the DLC, currently unavailable. For that, we'll have to wait until (or even if) Activision unveils a Gold Edition. Carnage, Cable, Magneto, Black Panther and Psylocke were the ones released. Psylocke, I presume, is done by the same girl who voiced her for the PS2 version. Needless to say, Carnage is the most interesting character for us, because he doesn't have a FF pack yet; the others do.
As far as what Tomato and I have been working on is just extracting samples from MUA2, MUA, and XML2 that had not already been collected into voice packs already and assembling enough voice clips to make the proper amount for a voice pack. The size limitation of Vox Studio 3 was a big hassle for actually playing long voice clips but it seems that with PSound it no longer will be a factor anymore for anything sampled out of a PS2 game. I have not yet tried to see if PS3 game sounds will be able to be accessed with it in the same way since I don't own the system or any games from it.
I'm familiar with PSound, it allowed me to extract the Justice League Heroes voices. I understand that it's compatible with PS One and PS2 consoles. I don't have PS3 games, but I've read that their audio works differently, just like Xbox 360 differs from plain Xbox.
So, I will be releasing XML packs, with some SMFOF along the way. If I finish everything, great. If I don't, we'll decide what to do with the unused XML/MUA material.