Many good points were made and most of you see our intentions.
To be honest and clear about this limitation, server stability is not an issue anymore. However, there are two main reasons to keep this limitation live. Both of them are based on our vision how THF balance/progression/play style should be.
1. We don't want to encourage players to train whole zones for any reason (exploiting, training others, blocking progression / leveling, etc).
2. We simply don't want to allow players to farm gear/AA/exp or power level faster than how they can at the current circumstances. (which is already pretty fast)
I hope it all make sense.
One thing we can consider here is changing the mechanics of the "punishment". Instead of porting the player to THF, something else could happen. something less annoying, yet good enough to withhold players from doing it.