Each of those weapons you listed either fire slow, or have low times to kill.
If by "low" time to kill, you actually mean "slow" (because they're opposites in this case), let me just remind you that the Splattershot doesn't fall under either of those categories.
Look, I personally think the Dynamo Roller is really strong. I'm not quite ready to call for nerfs yet, but I can understand why people complain about it. But even from a somewhat sympathetic perspective, I think the nerfs you've outlined are just ludicrous, especially for non-Dynamos. Slower swing speed
and no ability to aim during the windup? You might as well be calling for people to go back to the brain dead steamroller attack plan that was used during the Global Testfire; at least that way, they wouldn't be a sitting duck for a full second as they helplessly watch the enemy strafe to the side and blast them into oblivion.
This has been said before, but it bears repeating: Ambushes are something that should allow
any weapon to win an encounter. The mere fact that rollers are a bit more consistent at getting ambush kills does not make them OP.