It's like tendrin said - he may still be a bit crazy, but he's more self-actualized now. This is in-line with the very first depictions of him by Jenkins. Bendis made the Sentry a gibbering mess who could barely function outside of his own room and had zero agency. This new Sentry seems to actually be capable of doing things on his own now, which is a huge step forward for the character and a way of washing away the bad taste left by previous characterizations.