A late reply, but with review coming tonight I’m restless.
I feel ES has become sort of meh because it hasn’t scaled as well with the massive Stat increase of WoD. They tried to keep it alive by offering the 20% increased heal effectiveness, but I tend to roll RT on tanks and not for us them with CH, unless I know RT will fall by cast completion.
A couple of workarounds could be to simply increase the heal amount, a static damage decrease (say 5%, nothing game breaking but enough to make people go “shit yeah let’s being the shaman”), or a residual decrease in reduction, e.g. 1% or so per charge, so you have to commit to refreshing early or some such, along those lines of the previous.
Not backed by the mathematical thinking of others, but I’m also at work, and just thinking out loud.