TMX and MX Servers are often offline. (TMX Plugin often crashes like yesterday)
But MX Servers are offline the whole time since years ?

Will this feature come back or is it dead ?

TMX PPO servers should be online. If not, then they (or the controllers) need to be restarted.
Feel free to PM me here when they need to be restarted.

MX PPO servers are offline indefinitely though. There was sadly little interest in them when they were online. They were never as popular as the TMX PPO servers.

Also, as I understand it, Nadeo's updates to the game broke the functionality of the controller at some point (yes, years ago) and the servers were never fixed.

Also I'm not sure how it'd work with maps using so many different titlepacks these days. Only maps for the default titles would be able to be accepted for the servers. I guess that could work if it were coded into the system to prevent maps from other titlepacks from being used.

I wouldn't count on the feature returning anytime soon. But never say never.