In PvP, reduce the number of affected targets to 3 or 4 instead of 5. In PvE leave it at 5 of course. Frankly, there needs to be a mechanic that penalizes players that cluster. This is one of them. People complain about lolsmash...ok, is that more lol, than lol clustered lemmings? Plus look at all the mechanics that are designed to work against melee and sweep...all the stuns, knockbacks, and range gaining skills....plus the idea of simply not clustering since it only has a 5 m range.
That is a much better change. Also, another good point...there should be penalties to clustering for heals, etc. otherwise just stack on top of each other ad nauseam, especially with ranged and healer classes...there has to be risk/repercussions for that...no wonder so many people, esp sorcs/sages are happy with this nerf. I have rarely seen a situation where something was apparently thought out so poorly by development...at least regarding a single nerf.