FYI, I am not actually watching the WP.org forums, but XVE is not actually unmaintained per-se. I am sorry for not answering your requests, but watching these forums is an extra overhead for me. You can drop some lines here if you would like to see more from XVE: https://www.saltwaterc.eu/contact
There will be a drop-in replacement (called: XVE – XVE Various Embed) that will consider a lot of the requested features, including support for Flickr. However, till I can research Flickr, I have to get it ready for the v1.0 GA release. This is a completely new plug-in that happens to support all the old plug-in features, and more.
Flickr will probably make its way into v1.1 where I have plans for implementing oEmbed for the services that don’t provide a clean way for URL-to-embed translation without doing a remote call. If there’s a way to avoid oEmbed or any remote call (such as using YQL / Flickr API), the support will be there sooner.
Regards,
SwC