I RP my shadow priest (who started out as a guild NPC but took on a life as his own) as a "bard" in terms of combat ability-- his primary focus is emotional manipulation, rather than direct combat. If I translated him to a Pathfinder-system game, I'd probably want to use the bard class as a starting point and modify the specific class abilities, flavor text, and spell lists to suit the character (with the DM's oversight, of course.) This doesn't carry over to gameplay, however.
However, WoW doesn't have a support role, so a bard-like class would be difficult to implement. Even if you're giving the other DPS a boost to their output and reducing the enemy's effectiveness at the cost of doing much lower personal DPS, some idiot is still going to spam meters and try to get you kicked for being "bad." (Seriously, this is from someone who's seen healers kicked from groups for not doing enough DPS before, meter worshipers are idiots.)