I'd like to give you a little feedback on the melee mod nerfs now that I've had a few days to play with them...
Was it your intention to kill this mod, because I think that's the effect. Do some data mining in a month and see how many melee weapons have Berserker Fury slotted. My guess would be about 1% of the current number of actively used weapons. Because of the new ON KILL requirement, the mod is no longer a viable choice if going up against tough enemies. For example, I went up against some necramechs in Demios Tier 4 bounty and I couldn't get enough hits in with my Galatine Prime to kill it before it killed me. The attack speed boost never kicked in because those are mostly battles against a single enemy and it never died. No way to kill something before I was killed. That relegates the mod to conditions where the player is only fighting against low level minions, and a lot of them. Low level endless missions come to mind as the best place this mod would benefit the player... but in all honesty it's not needed in that situation. I can kill plenty of minions in a Survival mission without needing additional mods such as Beserker Fury. When I mod a weapon, I need mods that will perform against both minions and bosses because I never know what I'll be going up against. If a mod is useless against tough enemies, then... it's basically useless. There was always a bit of a ramp up using Beserker, which was its disadvantage, but the reworked Beserker Fury doesn't really have an advantage. An additional 15% attack speed boost over primed fury isn't an advantage if it never kicks in. It's a disadvantage.
Stacking Beserker with other attack speed mods is an interesting idea, but this should be a design choice, meaning, the mod would need to be re-worked with this in mind as its primary purpose. That might actually be something you'd like to consider to make this mod at least useful (personally, I still wouldn't slot it though if it was still ON KILL).
Instead of the ON KILL requirement, how about changing it to something that can come into play in all situations? I still think crit is a viable choice, especially if you can't stack it with other attack speed mods (I mean, it would only be a tiny 15% boost over primed fury), but if you really, really don't like tying attack speed to critical hits, then how about tying it to combo multipliers? That would be a much longer ramp up period and it would match the mechanics of Blood Rush and other combo counter mods. Tying attack speed to the combo counter might be too much of a disadvantage though. Might take too long for the speed boost to kick in. We'd need to do some testing.
Alternately, a different mechanic you could tie it to could be heavy attacks (although I don't have any idea how useful that would be).
Frankly, I think they only thing that needed to be changed was the ability for the mod to stack with other mods. That would indeed make animation-breaking speeds, but a mere +15% wouldn't do that.
P.S. I just had another idea that would need testing first, but what about tying Beserker to Orange crits instead of any crit?
The nerf is fine, it's still useful but less so...
There were quite a few people who started using this mod instead of primed pressure point. If you look at the numbers, it didn't surpass primed pressure point until the 3rd status effect (and even then it wasn't a huge difference)... so there was still a bit of a disadvantage there. I'm not sure it was necessary, but it is still useful after the nerf, so I can live with it.
Well, that's it. nothing Earth-shattering, but I do hope you rework the rework of Beserker.