Can Kelly create stability or will it be same stuff different Mooch?

No, because Trump is the problem and he won't be able to manage Trump.

Trump is a chaos monster. Nobody can tame him.
/cue Miley Cyrus
Kelly will try, and he will fail.

Maybe. The problem is the instability of his boss. I doubt Kelly can change his boss's behavior but he might get the staff in line.

You speak of General Kelly I presume ?
You do not get to be a FOUR STAR General without many years of demonstrated leadership. I would say, of course not knowing the man, he is the " Speak softly ... carry a BIG stick type ". Don't expect to hear too much publicly from him. The media may try to buffalo him out in the open but, he knows no need for them. Not his job description to pander to the media.
I would expect integrity, loyalty, and outstanding leadership in the Whitehouse from him.
On, the other hand I knew Moooch was short timer. Like the yappy little dog. Bravado, wrath, and threats are not qualities we have any need for.

GREAT POWER should be used with great restraint. Mooch is a dummy, Too big in his own mind. Like a yappy little dog.

Good point.

Yes.