Yes, level can factor in to the equation, but there is also the issue of how channeling interacts with feats. For example, the Cleric in my party had the Quicken Turning (Now "Quicken Channeling"
) feat, as well as the Extra Turning feat. Hence, the Cleric could essentially Channel Energy every round as a free action (well, immediate action or whatever it's called now) and still have the full roster of actions left for doing other stuff. Taking these feats was not some great sacrifice for the Cleric, since Clerics are not very feat dependent in the first place.
It should also be noted, that I too did not find Channel Positive/Negative Energy to be overpowered at lower levels until this undead side-adventure the party got involved in. At this point, I would prefer to see it toned down somewhat, but I want to reiterate that even in its current state, it is far superior to the old 3.5E mechanics.

It should also be noted, that I too did not find Channel Positive/Negative Energy to be overpowered at lower levels until this undead side-adventure the party got involved in. At this point, I would prefer to see it toned down somewhat, but I want to reiterate that even in its current state, it is far superior to the old 3.5E mechanics.