I use a version of the same team based on the cards I have:
I then try to play quickly and hope the board or I don't give them a 4 match. I have found there is no point in being meticulous. Sooner or later, they will get a match during some of the games no mater how "smart" or "careful" I am. Once I see their loop, I just retreat. A freeze will force me to help the enemy with most of the moves I could make at that point.
Amira would be nice, but you need all of your troops to mythic (I'm exaggerating), and in turn accept no gold from PVP in exchange for inflated enemy stats and difficulty.
I'll try the Amira/Manticore. Maybe I can cast twice and have a chance.