With the free unlock everyone gets, their buy-in price does not matter.
What the free unlock made worse though is the amount of machineguns used by players. I don't know the exact numbers, but I am fairly certain that 90% of the people with access to a machinegun use a machinegun.
It's getting to a point at which (in my experience atleast) out of my ~25 deaths 23 have been caused by either a zafir or a Mk 200.
And I don't really blame the players. Machineguns are beast in CQB. High ROF, mag size and caliber are deadly, even if the user still sucks so much that he needs thirdperson peeking and 50 bullets.
All that the SPMG/Navid nerf has done is that people stopped using them and switched to lower caliber guns.
I would like to see a reason to use something else than a machinegun.
Lower kill rewards for example. Such as 50 or even 25 $ per kill.
Making half as much money per kill would probably be a good reason to switch over to a assault rifle or a DMR.