Some thoughts:
Consider playing support of the people. Win by 5, play it, grab the Mander, draw 2 cards. Or get Streets of the Sisters. With Support of the people you can reduce the number of the mander, maybe even to 1.
I’d probably add 1 highgarden, another target for it, and a useful card.
Muster the Realm seems bad, you have only Wardens of the Reach for army cards. Winds of Winter seems much better than it in this deck.
Do you have too many limited cards? I find the Lannisport Moneylenders to overload on limited and also they can hurt your setups, because you cant play them with a limited location. Sometimes this prevents you from playing a good setup. Maybe the 1 cost lannister reducers would be better.