Exotics and Chem are pretty hard to come by so those guns should not be touched anymore.

The gun nerfs we already got are enough.. PKs are hard to get anyways. I play since 2013 and I still don't have the PSG1.. It took me less time to get to my 5000 spar wins (got reseted ) than It took me to get to my 100000 pks.

If they did make something like metro to all the popular locations than the streets would be pretty much empty.

Rewarding streakers should be implemented but after all winning every fight should not be a part of pking as you need much more pks for a reward than spar wins.

Only thing that should be added is the death timer (a period of time in which you don't take damage but also can't deal damage after you respawn) There should be a timer like on top of your character when you respawn that shows you and other players how much time is left.

I agree with everything you named on the 5th point.