Leum f they cut the damage by 50% then you would be doing the damage of a whole other player
Sure -- when the pet is charmed. When it's not, it's doing the damage of two or three whole players to ME. Or it's being stunned or mezed in preparation for recharm, in which case it's doing zero damage. If it happens during a big pull, then who does the healer heal -- me or the tank? And I won't even get into the level of interaction required to hold a charm pet for hours on end, knowing you need to react in a split-second no matter what, even while others are AFK. Chanters need big bladders, since they rarely get bathroom breaks. Finally, there's the cases of when you have no pet at all because the mobs are all marked uncharmable, or they're too high a level, or too low a level to be viable.
Given all those factors, the risk v. reward equation doesn't work for charm unless we're doing significant damage with the pet. Certainly a charm pet that does less dmg than we can do without it (summon pet + all the extra nuke mana) is broken. We're certainly not "lucky" to have a charm that reduces damage, rather than increasing it.
To be honest, I'm perfectly fine with devs deleting charm altogether. But that works only if our "support" role makes sense. And right now it doesn't. Crowd control isn't needed in many camps, and even where it is, it's only necessary for a few seconds of breaking the camp, out of several hours of experiencing there. And when it IS needed, there are plenty of REAL dps classes, along with priests and even tanks who can perform those CC functions just fine ... some of them even better than we can. Tell me how that makes sense.