This is a wonderful addon that fixes (almost) every single issue I got with the default Blizzard UI. My only issue is that when there’s more than one tank it’s hard to know who the job is ranked by.

Are there any plans on adding support to change the color of off-tanks?

Thanks! Right now if you are tank the color depends on who has aggro for the enemy (other tanks it's gray, on you it's green). I sort of ran out of colors to use, so it's only those two colors I can reuse without a bunch of rework. I probably also HAVE to keep coloring green if you yourself are any tank role and have aggro, just so you know yourself from other tanks in the group.

If you are the healer/damage role it just colors green when any tank has aggro for the enemy, or gray if a damage role has aggro. I might be able to distinguish assigned/leader tanks from "lesser" tank roles per the below (but lack the extra color to represent it since yellow is already used for tanks using taunt):

Enemy aggroes raid main tank/assist/leader: green (gray if you are tank role)
Enemy aggroes any other tank in the group: gray (yellow if you are tank role)
Enemy aggroes any damage dealer in group: yellow (orange if you are tank)

It may become too confusing if I make this distinction between main tank/assist/leader and other tanks, so perhaps it is best to just leave it as is (green for you tanking, gray for other tanks) and improve the addon description/readme with next version.

I see! So if I'm the tank and the other tank has aggro the nameplate is gray? Is the color the same for me?

Because this feature would likely only be useable by tanks (I'm a tank myself). I want to keep track on whether it's me, or my tanking buddy who has aggro at any given moment (so that either me or him can pick up adds that a DPS might've pulled away from us).

Does that make sense?

Precisely, it SHOULD already color green if you are a tank role and have aggro, but gray if other tanks have it. If you were looking over the shoulder of whoever is playing the other tank, on their screen THEY would show green and you as gray. So you SHOULD already be able to tell yourself from your tanking buddy/buddies just by that, where you two can sort of ignore the green/gray nameplates since either one of you is already tanking those. I really should update the readme at some point :D

Do note if "color gradient" is enabled: you will fade slowly from green toward gray as your threat percentage reduces to 100% (below which you normally lose aggro to the second in line on the monster's threat table, perhaps your tanking buddy) and back toward green if you regain high threat. Maybe try to disable "color gradient" for a bit then it should be easier to verify your tanking is green and other tanks is gray by the pure colors, then just enable "color gradient" again when ready for color fading.

Alright, I've updated the readme.md now for upcoming 3.5-release, you can see it below:
https://github.com/int3ro/Nameplates_Threat/tree/mikfhan

I assume this issue is then resolved, otherwise do let me know if it's still unclear (especially the bottom three paragraphs).