Shadowrun suffers from a number of problems that plague tabletop & PbP games. One is edition fatigue. What mean by that is this: the game is in it's 6th edition, I think, and there are players that like certain editions over others and will usually only play certain editions. While this is fine with widely popular games like D&D, Shadowrun is a niche game with a scarcer player population. The other big obstacle is the varying player approaches to character design, having to shoehorn them all into an adventure together, and somehow make it work and then there's the PbP planning stage for a 'run that takes so long enough players lose interest and the game folds...
I love the setting (it was the first for me to see positive Native inclusion instead of as cannon-fodder or inconvenient obstacle) and enjoyed both playing & GM-ing it and would love to see it flourish but it's always had an aura of misfortune about it. I'd definitely support seeing it succeed on GP and would offer to help a GM mentor project for it.
V:tM always suffered from the 'herding cats' issue with characters & motivations. Tabletop games seemed to be more cohesive and the characters had on games I ran, at least on the surface, compatible and cohesive goals. I think that was due to the players knowing each other and that often isn't present in PbP player ensembles. At least with Werewolf, there's an urge towards player goal unification baked into the game lore of W:tA that helps keep players on track... The newer Chronicles of Darkness I'm not so familiar with.
Anyway, enough rambling... I'd be willing to help GM mentor a few games in familiar enough with to maybe be useful:
DC Heroes (MEGS)
Call of Cthulhu
Shadowrun (may have to brush up on later editions)