Take my opinion with a grain of salt I have barely been boxing two weeks. But five years of theorycraft.

I have been against a 1 pally 4 shammy or 5 shammy group since well as long as I have known about boxing I HATE using FOTM things, With all the new advances in boxing and changes in WoW in the past year I did not want to make a mixed team so I went with 1 paladin 4 shamans.

I am only 24 atm but I am having a blast doing just instances. The things you can do with them are just so fun. Like 4 healing stream totem+earth shield+word of glory and let the healer dps the whole fight with stopcasting just in-case he needs a heal. 4 interrupts, 4 purges, Searing totems firing off. It does not matter who dies if one survives they all have res and I have not even made it to the fun of things like. Chain lightning, Chain heal, Anhk, My minds a blank but many more I am looking forward to.

I played a mixed group 4 years ago to level 40 and I did not find that as fun although not to much harder. I believe that's because I was not used to noticing everything from 5 class's at once yet so I was not getting the same enjoyment. Which also says to me a mixed group would be harder to play these days (Since best dps has changed form rotation to priority)