Actually, absorb per se is not an uber power. It's an equalizer. But it's not even FULLY an equalizer. At least in my experience, it all depends on the level of the force powers used by each player.
Take the following, for example.
I enter a server, I have absorb set at 2, instead of 3. The other guy obviously has maxed out lightning. I see him running towards me, so I turn on absorb. The other guy fries me with lightning. What happens?
I gain a little bit of force power while I'm charred to a crisp. So, apparently, absorb will not block ALL powers ALL the time. The thing is, everyone maxes it out so that it WILL block all the powers. But hey, that's their choice.
Here's a tip for the darksiders out there that I actually learned from watching bots play (if you can believe that). Assuming that you find a guy who doesn't run around with absorb turned on constantly, grip 'em first and keep approaching them. The other guy will turn on absorb, but hopefully, you'll have broken his stride to the point where you gain the initiative in a sabre duel and can kill him.