Mercs is an interesting feature, but like i said in previous posts, its so exploitable, mercs should be removed from the game until fast relog can be prohibited effectively.
Overall i think mercs are hurting the server more than helping it, i never heard players saying they play Fonline2238 because you can have mercs, but i did hear many complain and even leave 2238 cause of that flawed feature.
Then I will be your first.
I play 2238 because you can have mercenaries. (followers in general)
Which means, unlike most mmos, you can do things without being alone 24/7 (E.G. Grinding in Runescape) it's more like parrallel play half the time there, and can always have someone cover your ass even when all your friends are offline.
now those are some hugely amazing pros right there.