my level 35 mesmer had the following stats after i entered fotm (with cheap masterwork stuff and lvl 30 buff food):
-2.8 attack
-55% crit
-18k hit points
-2.3k defense
-900 weapon damage
having all the important utility skills and these stats, i dont see a problem to run the lower tiers of fotm with a low level toon. at a certain point you want level 80 in exotics, but until then running with up-leveled player doesnt make such of a difference and will make group finding much easier.