Anyway, are you keeping the old houserules? I might play something simpler and more straightforward. Oh and we're using Pathfinder rules?
Yeah, keeping the old house rules. Not using pathfinder in general, but you were using a version of the PF Summoner, right? We can look at PF classes on a case-by-case basis, but I'm not versed with the PF rules as a whole.
As far as adding a new person, roles to cover, etc, the original idea behind this was the party was all supposed to be psionic somehow, and from a land where psionics is banned (punished by Exile), and magic is heavily controlled as well. The world is a frozen wasteland, with what pockets of civilization that exist almost entirely contained in heavily-shielded city-states. You can read more in the house rules and other threads.
If archangel is leaving, I will probably add 1 or 2 more. You aren't absolutely required to play a psionic class, as everyone gets Wild Talent for free (and therefore is exiled...), but it would fit more with the theme if you did. Dreamscarred Press material is available, as is hyperconscious if you can provide the crunch (I don't have any of those books).