I wasn't able to go into the episode thing earlier. ( I was at work ) but I can now ^.^
RA has the edge in ep 1 & 2, particularly the casts. Ep 4 is geared more towards FO. HU is an all around solid class for any of the 3.
I find it hard to believe you had no problem in hard ruins at lvl 40 on any server, unless you had a lvl 200 mag and ideal equips, ability units and attack bounus units as an example. on other servers ( as well as this one ) and v2, this has been the case. That's talking as playing on multi-mode. Solo play has always been easier, there are less mobs and their stats are lower. Thats where I'd believe a no problem sernario for a lvl 40 in hard ruin.
Their are monster buffs in place on ult, mostly in eva and def. The bosses are buffed all around in ult. I think it was the equivalant of a lvl 20 s/d in addition to eva increase. ( anyone who knows for sure, I welcome the correction )
Hopefully this helps, and sorry if it seems like I wasn't being nice, I don't mean it to be that way.