User blog comment:Apprentice125/Changes From Battlefield Hardline Beta Outlined, Twitch Takeover Schedule/@comment-5485229-20150314045403/@comment-4215845-20150314080454

I think it's mostly to keep the weapons faction-specific for most of the game, which I'm personally fine with, but YMMV. Switching some of the weapons was done to balance out the faction discrepancies anyway.

And yeah, I loved the MP5K during the beta, but it I still believe that thing needs a nerf if it's the default for the Mechanic. It kills way too fast and it's really not that hard to use over range.