Currently, I see other classes doing 30K per target at times and we do only 1K to 3K per target. While other classes do over 100K, we barely scratch 5K to 8K (regardless of gear). We have not seen anything from Blizzard yet to address this and shadow priests have gone untouched.
Halo has a 40s CD and you need to be 25yd to 30yd away from your target to be anywhere useful. You're not very good at your hunter if you do that little at lvl90. You should be pulling over 100K on 15+ mobs.
Mind Sear serves a purpose and that is constant aoe. It is non-existant right now and blizzard noted it as a major problem and stated that it would be buffed by at least 25% on the beta. That buff never made it to production. Even at 25%, it would not be anywhere equal to other classes. At most it would need to be around 40-45% to be on par with other classes.