I also meant to say I’m genuinely curious about your reasoning as I’ve been tweaking my own skill tree that isn’t that far off from yours. What’s the setup for your gear, action skills, and playstyle?
[Edit] Also more specifically about Domino Effect… for 5 points you get 15% fire rate & 20% reload speed for 8 seconds after a crit. It’s a solid boost, not hard to maintain with repeated crits, and isn’t reliant on kills/seein dead. That’s all cool. I even run with points in it regularly, but it’s less of an “I need to take a tree this far and no farther” than it is an “I don’t feel bad about putting points here to get the next tier” kind of cool.
2 points in Violent Violence will give you 16% fire rate for 15 seconds at 2 stacks, and that’s with just the skill tree bonuses; without Seein’ Dead or Spy factored in.
Cool Hand is even better for reload speed as it gives you a flat bonus for each point on top of the kill skill itself. 2-3 points here is again a better return than Domino Effect.
That’s not to say DE is a bad thing, I just question it as a stopping point. If your goal is just the fire/reload buffs, you’ll get more out of CH & VV for a proportional investment. If you want to keep the points in DE, move some over from Salvation. You really, really don’t need more than 1 point… 3% of 1M damage is already more health than the average VH, and that’s lowball damage. 2 points is overkill 
If you need to go that far in purple to unlock Proliferation, I understand, and I have two suggestions for a more effective distribution.
One route is minimum investment: leave everything in T1 & T2 as is, remove Fugitive (optional, but I find it to be just as wonky as it is on Moze, and it’s mutually exclusive from ADS), and put the remaining point(s) needed just to unlock the next tier. That gives you more points to play with elsewhere. There’s also an advantage here in that you can still get the capstone if you use the Spy COM.
The other route I’d suggest is finishing the purple tree. Our Man Flynt with a cryo weapon (which we already find desirable for Zane) does the same job as Brainfreeze but easier. ADS & crit.