I love HBK's.. But the 4SP hardly needs a nerf. For one, the thing runs blistering hot, and a 40 point spread alpha and around 4DPS is really not that earth shattering.
It's a solid mech, that's it. If it really was that great of a performer, you would see them as often as a Stromcrow, or many other meta mechs, or maybe it is good you don't

For me though, you can't run 6's, gotta go with 4's and run extra heat sinks. I also think running an XL is a waste, you loose so much of it's tank power.. just do do something that a lot of other mechs can do better, Large lasers+ missiles. The HBK is a short ranged master.. to me it is in a very good spot.
A good player should be able to hit 400-500 in it.. But a good player can hit that in at least half the mechs in the game, if not more. To me that is not something that says, this mech is over powered.
I Do wonder if HBK's are getting hit with a resize though,, but for some reason i feel it wont.. and just for that reason, keep it how it is.. Nice quirks, for a mech that plays like all the lore i know of..
One tough little short ranged bugger, that if you don't pay attention to you are in a world of hurt.. but if you see it coming, you have the advantage, and its boosted armor is not going to help