I'd say builder -> resident -> mayor -> president -> EcoSomething

It looks a bit better because the colours flow better into each other. (well, except Orange, but Eco ranks look out of place anyway)

 

https://ecocitycraft.com/forum/threads/suggestion-change-president-rank-color-to-yellow.122625/

+1 for reasons stated in this thread. There's also barely anyone in the nether anymore, so in my opinion, it'd be fine if that and the End shared colors.

 

Yellow is gross, though.

 

I like the yellow above the Orange...

 

Tycoon?
also I see what you did there. In that case, would Tycoon look like this?
[Tycoon]

 

PLEASE MAKE PRESIDENT GREEN COLOR THIS WILL SAVE ME PLEASEEE

 

Well I mean most of Ethan was a copy anyway, save for the minigames :p
As for your EcoLeader argument, I recently posted a thread about the light blue and @kukelekuuk00 brought up the point that it may look too much like staff. And having yellow-orange-blue-orange-orange would be confusing af.

PS: By reading through these posts, I feel like some people forget that the Tycoon rank even exists... maybe adding asterisks (dark gray this time because black was ugly af) would be another suggestion to make.