[@Double] A shame that you have to leave. I personally liked the character and saw no problems with him whatsoever. Again, if I were you, I could've just put him simply as mortal or just overpowering him as a weakness. Afterall, that's pretty much the main weakness for Sentinel anyways. (Or if anything, maybe something for the armor perhaps? Like a power time limit? Just an idea though)

Again, I'm not exactly sure what's going on between you and the GM, for I really don't see any problems with the guy. With all do respect [@The Kid Lantern], I say the character is fine as is. 

That is only if you, Double, still have a bit of interest yet. If not, I bid you my farewell and hopefully you may give it another shot some other time.