Manaleech was a bit of facetiousness because I don't think it would really help, the other two are intended to be kept separate as different ways to attack the same problem. The Rage thing is my favorite as well, though, for exactly the reasons mentioned. Berserker is surprisingly mana-hungry.
Any proposed "cooldown" on this type of raiding should be randomized alongside a resource cost that is achievable by a group of individuals within the cooldown period (but difficult to impossible for 1-3 people to pull off). Raiding every day should be possible but not predictable or guaranteed, and involve a precluding effort on the part of the team.
Dyron plays the class well and unfortunately Outrider was not intended to be played by anyone with half a clue. It tracks for itself and really only requires you to occasionally push a different lever. Someone who understands game mechanics can quickly become an absolute monster with it. It's the same reason I played it, and Azefel, and Dreacor - super trolly with minimal effort required.