I'm fishing from the bank + the cover isn't too heavy.

 

Powell Max 683 6'8" MH XF

 

 

Give it a shot. It should, I personally use a minimum of 7ft when I frog. 

I think so. Not ideal, but if you're fishing pretty light cover I think you'll be fine. That rod can do just about anything. I would throw frogs in light cover on the endurance 723 and it was ok

I was going to go with the 7' but I was afraid of getting hung up in trees from the bank. Will the 6'8" MH have as much power as a 7' MH Powell Max still?

i would say so. to go up in power u would need the 4 power max

I really think you'll be fine. Try it out and if you don't like it you have an excuse to buy another rod 

The rod will handle the frog fine, heavy cover is what it won't heavy well.  If you aren't fishing heavy cover you should be ok.  Just be aware of your hook sets.  It will be a little harder to drive big frog hooks home with a shorter MH rod.