I like using weird setups. i tried to use Braced autoguns with this keystone. Now i havent tested any breakpoints but on paper it should at least be a helpful buff with reload speed and finesse damage, but because stacks by default dont build up unless you score a headshot kill, this setup is incredibly difficult to maintain maximum efficacy.
Problem of course is because brautos tend to have crap breakpoints even on weak points. For the agrippina this isnt as bad, but for the others this is awful. The point of marksman focus is to net some useful breakpoints. To be fair it does, once you have max stack, but the issue is getting there in the first place is easier said than done on many weapons. Yes, you can take camouflage to offset this somewhat but this is just not a fun way to play.
If marksman focus can not only be built when only getting weakness point hits, instead of on kill, it will instantly become that much more useful. As it is now, it benefits weapons that already have good breakpoints, but is useless for those with either very high or very low damage, since they already 1 tap pretty much all high value targets, or struggle to even kill basic groaners.
Maybe one of the modifiers can be made to allow stack to build on weakness hits? I of course would prefer if by default this is achievable.