Random Generator gave me Shimatsu the Bloodcloaked and Shield Sphere. That's quite the uphill battle, since I don't know anyone who likes Shimatsu. Here's an attempt to make his ability mean something... that's going to be one large creature, even if it can't attack.

Wow. Yep, uphill battle indeed. And you still need to sac several permanents; say 2 to get a 4/4 that can't even attack. I'm not liking it. Perhaps the mana cost could come further down. Or perhaps you could remove defender and add the Clockwork wind-down ability inspired by Shield Sphere's ability. I don't really know.

Yeah, uphill :) I like the design, but wouldn't normally play this. But OTOH, I can imagine occasions when I might, if I'm playing a deck with lots of wellsprings and spines of ish sah, or want to trade up some of my extra lands.

Would giving it P/T equal to the combined P/T or combined mana cost be too different? Alternatively, give it flash? Or perhaps. "0. As ~ comes into play sacrifice any number of permanents, and this comes into play with that many +1/+1 counters on." (Possibly with flash, possibly with double counters, possibly with defender, possibly with reach.)

Clockwork just feels like a different drawback to me. I know it is well loved, but it should still make some players feel bad, even when they like it. Also, doing this without defender won't allow it to get as big as it can get, and that's the part that seems exciting to me. I would have mentioned Fling in my original comment, but that card is bandied way too often. Maybe I can mention that this will trigger a Mosswort Bridge all by it's lonesome. But, I agree... at what cost?

Flash seems like a good choice, however, since it seems the least invasive and allows the wall to work as a combat trick, as well as something to do with an already dying creature. I also added 2/2 to give players "a free sacrifice", so now sacrificing a single creature in response to removal leaves you with a 4/4 wall... that feels a bit better to me. I Increased the casting cost by as well. Not very practical in real magic without some silly combo behind it, but an insane obstacle to deal with in limited, where creatures rarely get larger than 5/5.

That seems like a sensible set of changes. It's a card with some interest to it now, which Shimatsu never really managed.