A fine idea, but the limitation of ESR to 52.x is useless for some of the more valuable legacy extensions – 52.x falls below their minimum requirement.
56.x would be saner, would be more broadly supportive of the requirements of end users.
WebExtensions is not a panacea for performance issues. The more that I introduce Firefox 57+ extensions into my workflow – attempting to move away from legacy extensions, the more I have trouble with Firefox. This seems to be particularly true with 55.x, where the potential for improved performance (e.g. virtual tabs) may be offset by a significantly increased likelihood of extension conflicts.
Attempting to resolve conflicts, in the absence of a suitable extensions manager for Firefox, can be shockingly, unacceptably time-consuming.
Take the time saved by virtual tabs, multiply that by between five hundred and a thousand. That’s something like the amount of time that I have spent on troubleshooting 55.x. So whilst I’m grateful for the focused performance improvements in one area, the bigger picture is a PITA, not time-saving.
That’s harsh, but I empathise with the frustration. Firefox transitioning to WebExtensions has become a roller-coaster of joy and pain.
Just rarely, I fire up extended 57 on a Mac. It’s a shadow of its former (pre-57) self.