Here's one of my own. We know about the TC abuse on infiltrators. That is, cancel it right after using it for the least possible amount of cooldown.
Does 5A evolution of TC help with cooldown if the aforementioned shenanigans are engaged or does nothing change?
It depends.
If your stat sheet cooldown (what you'd get if you stayed cloaked the whole time) is longer than 3 seconds, then the minimum it an be shortened to (cooldown if you break it immediately) is always 3 seconds. This is true whether your stat sheet cooldown in 4 second or 14 (or anything over 3), so in this case that evo doesn't make a difference, assuming you break cloak immediately.
Theoretically, it can help. If your stat sheet cooldown under 3 seconds, then you will have the same CD whether you break it early or stay cloaked the full duration. Of course, this is not usually a very appealing way to build an infiltrator, since you have to stay very light with your weapons and/or sacrifice weapon damage for carry capacity.
I still always take it unless I'm playing a character who I built to use melee as a major damage source. If you stay cloaked for any of the duration, even a couple seconds to line up a shot or move, then it will help to shorten your CD in those cases. Also, I don't like feeling rushed by the need to break it fast, it makes me miss more.