Hopefully, in the next release, the quicklook plugin will continue to be used.
The existing beta version has been testing for 5 months and is about to launch the next official version. As a loyal fan of Zotero, I hope to retain the support features of the QuickLook plugin in the new version. This feature is unique and distinguishes it from other document management software.
I actually remapped the key quicklook key from spacebar to '~' in the plugin code and installed the modified xpi, but that did not fix the problem (working on Mac), so there may be more to it than the last post implies.
There is a workaround (Enter, Cmd/Ctrl-W), but it is too slow and intrusive (it takes you to a separate tab and back) to allow quick and successive review of many articles, which Quicklook was great at. Hopefully one of the developers or volunteers will have the time to look into it.