I'll agree with Rascal. Mercs were hated by most who participated in pvp. There's basically nothing to justify them to exist. Saying "they can be used for those who have less players" is not valid because they can also be used by those who have more. First swarm, then merc swarm.
Even though mercs got some nerfs, it still wouldn't hurt the gameplay at all not to have them. At least not the energy, bg and mutants. Slaves, dogs, brahmins and some single shot guys aren't a big deal.
Imagine the problem with mercs like this: with avenger, drugs and BA you've got a Hammer worth of let's say 25k caps. If you have 4 bg mercs, you have a hammer worth of 100k caps. If the player wanted to use those caps on common gear, he would get 4 hammers but he can't use them at the same time. But with mercs the player can just get a massive hammer and land it on enemy's head at once.