Korean dev view is that rohan has to be pure party oriented farm and pvp wise, just look at how the buffs changed, from being able to buff everyone you can now only buff people in your party with auras, the time of playing solo is over. Both the USA & KR department agree that you shouldn't be able to farm solo (unless you got a really OP DPS char). They want people to play together and party up to farm.
I support this view but I do see issues since not everyone wants or can create their own farm team nor can they always party up with people. This leaves them unable to XP/Farm in the mirror maps and thus behind on the others. Then again playing only a support char makes you depend on other people(PVP and PVE wise), you can't give a support the killing power of a DPS so at that point you're stuck. This is similar for rangers/vit dekans/avengers who can only pvp but farming is impossible or very slow. The only thing I can suggest is to make your own DPS char (preferably a predator) and use that in combination with your priest to farm. The other option is simply to wait for people to party you. They will not change the way mirror dungeons work because it won't allign with their vision of what the game should become.