I've been asking for this for well over a year. Nothing yet. I think they need a fairly fundamental shift in design thinking.
It's not just an issue with merge requests or issues, it's more of a general thing – the colour palette and typography do not make GitLab easy to scan in the same way that GitHub is. I find it requires much more mental overhead to parse GitLab.
@Sarrah: I put some of my thoughts here: https://news.ycombinator.com/item?id=16214892
Also possibly worth mentioning, I have the same problems with much of the marketing site and blog, not just the application.