I don't have my book here to compare, but isn't he a bit light on resistances for a high level monster? Other than that, I like the rest of it. He has all the other requirements of a solo (mobility, crowd control). I like the fact that the flavor is very internally consistent (sloth dude has sloth-like powers), if not the flavor itself. But, I think that's more me than anything. To me, ooze doesn't scream sloth. Gigantic fat guy with fat pseudopods (ew, fat pseudopods) screams sloth, or... a sloth.
My campaigns usually get more laughs than applause.
Actually, the ooze thing would work great if he didn't look like a black pudding. More like an ooze with chubby arms and a fat, melty face. Though that would work grand for Gluttony, too, if you were going for a seven deadly sins thing.
I like the ooze minion generation, but I don't think they'll have enough of an impact on the fight. They'll mostly appear and then get wiped out by an AoE attack.
I would clarify that the Split ability is a Free Action and make it so that the minion attacks immediately upon spawning.
Also I think the minions are a bit weak. 15 Damage isn't that big of a deal at this level. Maybe add immobilized (save ends) to their attack. It makes them more dangerous and gives great synergy with the Lord of Sloth's Eneverating Psuedopod.
But I basically took a normal black pudding and advanced and enhanced it to make it a solo. The minion feature was part of the normal BP. I just advanced the minions to make them appropriate to their new level. You think they need to be stronger yet?
And does anyone know how the normal minion feature works on BPs? Do they attack immediately upon spawning or no? If yes, then I won't need to specify such.
Now you're making me think. Erm. I used a similar monster, once, slaad spawner, I think. I believe it said in the text that their initiative order was right after the baddie's. I could be wrong about that, though.