If gear is up to par for the content then for my raids it would not be an issue. The only current content that has a melee penalty is HM/NMM Toth and Zorn, and that only becomes an issue when you have more than 2 melee in an 8 man raid, which for my raid groups is not an issue as we are slinger and commando heavy. In fact we used to run with one regularly until he quit.
Good point, however this fight can be glitched very easily by not breaking toth out of his frenzy(or what ever it may be called). I'm not a fan of doing it like this, but if you have 3 or 4 melee its really the only option that is viable. Also, when pugging it is much easier to do it the glitch way since 90% of people still seem to have issues staying out of range of fearfull.