Why the pet exp penalty came about?

[goshozal]

1) It applies to all pet classes, including charmed pets

2) It only applies while solo, and only if the pet does more than 50% of the damage for a given kill. There are ways around this mechanic (mem blur for enchanters, reclaim for mages, and so on).

3) The same penalty was on live, and therefore it was implemented here. The reasoning for it was that mages could do nothing but chain cast fire pets and /afk their way to 50 during vanilla. Verant answered the QQ from other classes with the mighty nerfbat.