I'm assuming by plug-ins you mean add-ons. I've ported three of my add-ons to WebExtensions and plan to do the other two eventually, but one of them is with very significant loss of features. Especially constraining to me is that apparently WebExtensions allows at most one BrowserAction (toolbar button) per add-on, and also one top-level context menu per add-on. This is all consistent, I suppose, with the current fashion in user interfaces toward minimalism, and keeping user-operated controls (remember, program or be programmed), if not non-existent, at least tucked away out of view most of the time. I certainly count myself among the dissidents, who miss when Firefox wasn't trying so hard to be just like Chrome.