For 2) as the link you posted pointed out it's by default in and for the few that like getting these notifications there's a out-in button. I'd agree that not having this be a default is a little bit bad UX but not having it at all is really bad UX.
I agree it makes sense to make this configurable. I've created https://gitlab.com/gitlab-org/gitlab-ce/issues/32383 to discuss.
- We're working on improving the UX. Issue filters allow you to type now. UX team work can be seen in https://docs.google.com/presentation/d/163xL_FLQLsWD8Yv9GfkR... and https://www.youtube.com/watch?v=NtDzyHnedoE The UX research in https://docs.google.com/presentation/d/1ZE9BNAnIPDKxgSyQU5su... and https://www.youtube.com/watch?v=k8-Jto8FTmA Sorry for the general answer, I can't be more specific since I don't know what flow you mean.
- As mentioned in https://news.ycombinator.com/item?id=14354087 some people like getting their own notifications, but maybe we should make it configurable.
- GitLab.com is slow compared to GitHub.com, we're working on this in https://gitlab.com/gitlab-com/infrastructure/issues/947 The GNOME team is looking to self host so they don't have this problem.
- What is the nr. 1 thing you would improve in the review UX? I'm excited about https://gitlab.com/gitlab-org/gitlab-ee/issues/1984
- I think mass updates to issues are getting some love in https://gitlab.com/gitlab-org/gitlab-ce/issues/28340