Is bard charming viable at higher levels?
 

In a xp grind duo/trio? Basically, a bard replacing the role of a charming enchanter. Is the mana cost going to force some downtime, and are there any ways to mitigate that?

Personally I don't do chanter-style charming where you keep a mob charmed for the entirety of your grind session, because refreshing the charm every 12 or 18 or whatever seconds for two or three hours is ridiculous. Especially when people are going to want you to be playing mana/heal song, melee buffers, snare... it's just too much. I keep my charm memmed and I use it when my group gets an add as a means of CC and extra DPS. When the other mobs go down, the pet becomes a pull.