Can you explain what you mean by "patch stack"? I can roughly guess what you meant but not sure. Do you mean rebasing changes while to preserving the diffs of what you were reviewing? (I find that essentially no Git service I have used does this well)

Personally I think I got used to Git since it's 99.99% of what I use today. There are definitely pain points to it, but just like most people it's kind of become "the way it is", which I don't think is healthy. While Git has helped revolutionized the way SCM works, it's far from perfect (and it still does certain things worse than a traditional centralized SCM like binary file management and renaming files), and I think its prevalence sometimes puts people in a collective blindspot/groupthink. Imagine if you are in your 20's and Git is the only SCM you have used, everything other than Git would either be old-school or weird.

I definitely agree on GitHub though. I think it's quite nice for small projects (I manage one myself) but I don't see how it's usable for a serious large software project for reasons you mentioned. Even simple things like correctly linking issues together, or code review tools just seem severely lacking to me.