I wouldn't mind doing splits, at least one, probably. For heroics. But I certainly don't have the time right now to maintain more than one alt at even a moderate level. I know many people in my guild probably wouldn't have the time to even do that. My guild isn't really hardcore enough right now for splits. Probably would have to raid a full 4 nights during progression to make it fly, or have 3 hours raid nights instead of 2.5 hour ones. (We do occasionally extend a bit on progression content if close to a kill and/or during new raid tiers.)
Could consider adding Tuesdays though if everyone could make it, I don't know if there's any longstanding conflicts with anyone, but our official schedule has just been Wednesdays, Thursdays, Mondays since this specific group formed in HFC. With alt runs/fooling around on Sundays.
Would enjoy doing splits more if I could have more than one DH on the realm, as during HFC I played two different DKs on two raid teams on the same server (though it didn't start that way). Still playing around with the idea of leveling a second DH and seeing if I get better legendaries on her, since I just hit 4 mediocre to bad ones on my main. AK 20 instantly is nice, but it certainly would be quite a bit of grinding to get up to point 48/49 (with 35 in veng) where I am currently. I don't know if it would really be worth it, having to juggle server transfers and losing stuff (unlocked artifact appearances, etc.). Otherwise I can play my mage as an alt I guess.