I think this topic is worth visiting again.
At this state, I wonder if it is possible to remove fiber in a backward compatible way given the large packages ecosystem Meteor has and the amount of code that has been written on top of it. It is the legacy of Meteor embracing coroutines and async/await style before JS ecosystem finally adopted it.
I like to be pragmatic rather than idealistic, so I really question the value of removing it, is it really worth the effort? or should that effort be directed to other Meteor potential growth areas? in fact, in some regards Fibers seems superior to async/await. Thus alternatively, the Meteor community can look into maintaining the fiber code base instead of removing it.
Either way, I think the consensus here is that something has to be done.