Totally agree on the project discovery bit. Noticed the same thing when I played with it. I added a couple tickets to try and encourage them to fix it.

* Increase the prominence of gitlab hosted projects on about.gitlab. Project search, trending, curated lists. - https://gitlab.com/gitlab-com/www-gitlab-com/issues/558

* Trending project data by language (js, ruby etc) - https://gitlab.com/gitlab-org/gitlab-ce/issues/13475

* Allow projects to flag themselves as looking for contributors - https://gitlab.com/gitlab-org/gitlab-ce/issues/13502

Give them a +1 maybe they will put resources on making gitlab more oss friendly