Well, they've been portraying Talzin as a chessmaster, it's no coincidence we all compare her with palpatine in different ways. Because of this i'm pretty sure she has some larger plan. I don't think they're galactic-domination flavored, but something more intimate. I very much doubt they'd ever give Palpatine any more real backstory through TCW after keeping him so ambiguous all this time, so i doubt she's connected to him through Plagius or anything. Though i could see a larger vendetta against the Sith working, well of course failing but working story-wise. Whatever it is, i hope they've already thought of it and aren't playing completely by ear because we could end up with a tangled up mess otherwise. I also would prefer Talzin not end up killing Ventress, i just can see it happening if they took the characters in certain directions. I could also see Ventress kill her, and perhaps they'll end up doing that with a throw-away line like 'we'll never understand her true motives' by Dooku, if they can't figure out what to do with her. Of course that'd be cheap, but shows have done worse.