There isn't really anything wrong with "farming" per se. Everyone does it at one time or another, even if some don't want to recognize it for what it is.
Having said that, I can't see the developers keeping the level 1-54 power leveling for the long term. I've just got a feeling that the nerf bat will be taken out of the closet. I would hate to see it disappear entirely, for it has done much, in my opinion, to eliminate the mind-numbingly boring, tedious grind to level 50.
My suggestion would be to restrict teams to about ten levels on these farming missions: that is 1-10, 11-20, 21-30, 31-40, and 41-50. Or something similar. Also, perhaps scale back the amount of XP obtainable on these missions by about 25% or so. Then make each of these mission groups available only on one or two particular maps: for instance, level 1-10 missions could only be done in Atlas, and 11-20 in Steel Canyon, etc.
