Right now it's Massif, High Amuka (ranking up), and High Entity as an anchor I wouldn't be able to win without. It was great before they lifted the Level 30 cap. I was even ranking up all of my old Cat 4, 2 element Dragons that I had fed to Level 40 back when the Dragon Market was paying off so much I hardly had to use it! Now there's no chance of that.
I would suggest that if they want to make the fights tougher, that they should lower the threshold for ranking up, but that would only do a little good since getting victories is the problem in the first place. It's particularly frustrating because they know it opens the door to hackers and then they turn around and want us to police there own game for them.