Here's some pictures I took with TMNTC Leo, NECA LEo and Revoltech Leo. In comparison with a Marvel Legends Deadpool (6"), MOTUC He-Man (7") and ThunderCats Classics Tygra (8")
Personally, I think a Shredder figure on the height off a MOTUC figure would have been a nice "fit-all" size, maybe a tad bigger for good measure. Not overly too big for the Revoltechs, but not shorter then the TMNTCs.
Cause, It's okay with Krang/Cerebral to be giant sized, I think it fits him a lot better, and is in line with the vintage large Krang figure.