Man, it would be absolutely crazy if they talked Alex into recording a new album with them. I wouldn't mind hearing Glen on a TestAmenT record again. Eric will probably play a lot of solos no matter who is the second guitarist.
It would be a nice idea if they released a CD with a lot of special guests (since they had a lot of members come and go in the recent years and some of them aren't on any record)- have Smyth do a lead or two, same for James Murphy and Metal Mike, have Jon Allen, Johnny T, Gene Hoglan, Dave Lombardo and Steve Jacobs on a couple of songs or maybe Chris Kontos and Asgeir too and of course Louie and Paul, bring back Derrick Ramirez for a couple of songs (both on bass and guitar); have Zet and Chuck sing a song together or Chuck and Eric share vocals on one song (not on the whole album, of course)- it would be something special, I think. Besides, some of them had been in the band during the writing process for the new record and their ideas might never surface..
Or record two albums (one with old members and special guests and the other with the current-whatever-this-means-line-up)...or 3 (the third with the original line up with Greg, Louie and Alex).
Ok, enough dreaming...
Still, if Alex does the leads, even if this wouldn't mean he's back in the band (and it surely wouldn't mean that, 'cause he's other commitments and interests), I'd be super happy and could wait for the album another year. His jazz experience could really enrich the band's sound and make it even more original... this could be something really groundbreaking.