Unfortunately I'm really not sure whether my group would be interested in running a different system. My group is a pretty sheltered one. I’d say that there are 4 players in the group at the moment (there’s another player that’s technically in the group, but he hasn’t attended a session in 6 months now).
Out of those 4 players, only 1 of them owns any books beyond the PHB. On top of that, outside of the one-shots I ran a while back, only 1 player in my group has played something other than D&D. When I did run the one-shots of other systems, one of the players was so against giving them a go that he was simply not going to attend. I convinced him to attend a session of Paranoia that I ran, but that went over like a fart in an elevator, so he didn’t come to any more.
So I don’t know if they’d be willing to play another RPG system on an ongoing basis. I really think a couple of the players in the group like playing D&D, as opposed from playing RPG’s (or possibly even fantasy-based RPG’s).
Personally I’m interested in a number of different RPG’s. I’d love to play a Call of Cthulhu, XCrawl, Feng Shui, Year of the Zombie or Paranoia campaign. I doubt that would happen with my current group though.
I feel your pain. My Pathfinder campaign from a couple of years ago had BARELY reached 8th level by its conclusion . . . and already I could see the drowning tides of rules and crunch that awaited me the next 3-4 levels.
Truthfully, the only thing that saw me through the last 2 months of the campaign was LIBERAL use of pre-made NPCs, with basic adjustments in feats and gear. The Pathfinder Gamemaster Guide and Rival Guide were my only hope.
If your group is truly a fan of the d20 / 3.x style system, but YOU want something easier to actually RUN, I highly, highly recommend taking a look at Fantasy Craft. It's definitely a part of the d20 / D&D family, but redesigned to provide a more consistent play experience, AND be easier for GMs at the same time. Complexity-wise, it's no better or worse than Pathfinder, but once you understand its basic NPC generation system, you can make NPC char gen as complex or simple as you want, without sacrificing flexibility or playability. Fantasy Craft fit my GM style to a "T."
To be sure, it slaughters tons of "sacred cows." The two biggest ones being armor is damage reduction, and spell casting is not even remotely "Vancian--but its a very compelling system, if your players truly don't want to drift too far from the D&D family tree.
One thing I've also discovered --- your players will largely take their cues from you about your excitement level to run a new system. It's not enough to be "interested" in running a different system; you need to be
enthusiastically committed to running a new system, and expressing that to the players.
If the players can REALLY see your enthusiasm for a new system you want to try, they'll be much more willing to give it a go, in my experience.
One of the things I noticed about the systems you're interested in trying---they're all RADICALLY different from D&D, both in rules, tone, and genre. That's fine, but would your players be more receptive to switching if it was to a D&D variant, retroclone, or even something like Savage Worlds that recreates the "bones" of the core D&D experience, even if it doesn't go about it the same way?
Having played Savage Worlds now using "familiar" fantasy tropes, I can say without hesitation that it is a FANTASTIC vehicle for playing a "D&D-like" game, while being much more rules-lite, elegant, and radically easier to GM.
All said though, despite any of my suggestions I think the pre-destined break for having a baby, and an opportunity to just be a player for a while (4-6 months) would / will do a world of good.
