Just ran 6's arc this morning with 6 people, mix of incarnates, a 50 with zero incarnates (me), and some not50s. We ran it at +4. Some deaths here and there. Massive bloodfest in the final avatar smasher fight. End result? Team said they felt Strong and Pretty (these were not the words that were used). Badges all around. Right level of toughness, team mix, player count.
Team was Run What You Brung. Nobody alted to change team makeup. It was purely what everyone just wanted to play. We had 1 scrapper, 2 tanks, a troller, and a dom. up against 3 54+2 avatars, and it was amazing.
You can have a not-boring, challenging, FUN team.