I'd almost forgotten about TW:MD. (And it's already playing in the UK?) I remember thinking I'd check it out (torrent-wise) just to judge for myself how it went... But I find myself not caring at all, right now.

I agree completely on Jack likely checking out as a solution for the 'nobody is dying' problem. (Or at least becoming mortal, so they can kill him off in the next episode or series.) And I think his untimely death wouldn't affect Jack guest starring in a later, completely Gwen-centric TW: he's been traveling through space and time for how many years now? :-p (Though they'd have to pile on the make-up or the CGI.)