I'm going to preface this with the request: Cryptic can we please have Tholians in the Foundry! Ships and Ground mobs! I think I'm right in saying that pretty much all the authors would be stoked to have them in.
Now that we're done with that, here's the real discussion topic: If we get them, how will we use them?
Personally I was thinking of making them a sort of chaotic ally in a mission. Something where you would have to temporarily work with the Tholians for the greater good. Maybe against the Borg or 8472. Would be interesting to get the Tholian take on the 8472 infiltrations.