A ongoing. Problem I see are the completionists etc. voicing their opinions against any XP banking system that will allow them to bypass some or all heroic content if enough is banked. These players represent such a fraction within a fraction of the player base but are highly vocal. They like the current system, have mastered the TR grind, and seem to oppose alternative systems that other players may enjoy more than 1-20 like them.
A XP banking system for TR lets capped characters stay at cap a while longer, and lets them enjoy the character they spent so much time building. Some builds only really shine at the higher levels, and they should not be forced into a system in order to increase their toons power (which is what many people want). The current system only reaches a certain portion of the player base.
To quote you guys, you don't "HAVE" to bank XP at cap before TRing. Keep doing it the old way if you like. Let us who want to farm our XP at level cap (even if it is at a reduced rate) do so. Everyone is happy!