editing...
Quote Originally Posted by Feilina View Post
LotrO initially (SoA-times) has done a good job with that. They had a Loremaster to debuff enemies (pretty powerful) and Burglars to buff the group, pretty powerful too. Sure there where bosses hitting hard and therefore it was wiser to choose the Loremaster but it always could have been done with the burglar. In raids you typically had both of em.
Unfortunatley the community wanted tohave a mage and no Loremaster, they also wanted to have a thief and no burglar. And as time passed by Turbine changed em, sadly if you ask me.

The debuff mechanic used by the bard is good, it takes high resources (TP) but offers good use (-10% dmg dealt by hitted enemy). And it is rough, as time goes by, to keep the debuff up.
You mentioned them being powerful, and that's part of the problem. When support classes aren't useless, they often hit the other side: Being so powerful they're required. And that is just as much an issue as a support class being underpowered, because now instead of nobody wanting them, nobody wants anything else.

A comparison can be drawn to tank and healing classes, which is a fair comparison. However, there's already an issue with an overabundance of DPS compared to other classes (Let's face it, folks flock to DPS for reasons I'm not going to get into here). If support classes enter the game and become a requirement (Either due to player perception or due to the game being balanced around the assumption you have one), that's now going to be "one tank, one heal, one support, one DPS", further reducing the available slots for DPS. And I guarantee you the pool of folks playing support won't come entirely out of the DPS, so that's less people playing tanks and healers on top of it. It won't exactly ruin the game, but it's going to take an already existing issue and make it worse.