I played a lot of pickups the past year, and as most of you know I played most of them as heavy weapons guy. I am not out to clobber the class, but I think over-pressure, OP, gives HWG an advantage he doesn't need.
If you look at pickup statistics,
http://parser.ffpickup.com/v2/record/most_kills_defense ,4/5 top kill records on defense are HWG. HWG is by no means weak class. The class has the most direct and easy form of dps, point and shoot. Top HWG's are top because they mow scouts down every run, not because they consistently OP. OP is superfluous to being a good HWG. OP allows a HWG to be less strict with his positioning at choke points, and get away with sloppy play. I believe the design of OP was to help stop the flow of offense in a meta when the game was much higher cap than it is now. With the changes to bhop speed and cap, as well as jump pad automated runs, I don't think is necessary anymore.
Another reason to remove OP is because of the damage it does to spys. OP is at a cooldown such that it can't stop scouts every run, or even medics on some maps, but it can always catch a spy. I know some people aren't a fan of spy and are happy he isn't in the meta, but he is unfairly castrated by this.
1. The HWG can counter spy every single run with OP.
2. OP creates a gap between the HWG and the spy at no cost to the HWG. A soldier shooting his feet with a rocket takes damage, a HWG does not.
3. HWG is already the best spy detection, if the spy is invisible, the HWG loses nothing by sweeping the area with his gun.
4. The most effective gap closer the spy has to close the gap with HWG is a frag jump, which is currently double countered between OP and HWG's damage output.
None of this even touches on the fact that the physics for OP can be buggy, sometimes launching people away at huge speed or pulling them backwards.
TL;DR
Over-pressure is from a past meta, it's unnecessary.
It allows sloppy play.
It unfairly nerfs spy.
It's buggy.