How effective are 2 mistweavers in a raid of 17-20 people. We run druid shaman and disc atm and the druid wants his monk and priest is going DH to tank. So would 2 mistweavers be ok for a raid or should 1 just reroll something else. keep in mind this is for legion raiding.
in regards to legion we have no idea what class balance will be until beta in a few months (and even then it'll change some)
but I mean as long as you're not a fairly high-end mythic guild, any comp should be doable, so wait until then, but if tank healing stays the way it currently is, I do think paladins have almost too much to offer to not want one, but It's really up to you,, if you think pallys aren't fun, then it isn't worth doing as it probably won't halt your progress at that level, unless your guild is really high end, especially if they completely rework disc like they're saying they will
I don't see what's wrong with double mistweavers. The only healer comp that is questionable for now is double disc priest since they cannot shield the same target.