Issues on Github consist not only of bug reports, for example, but also of feature requests. If, for example, you only display issues with the label "Enhancement" at https://github.com/Eugeny/tabby, there are already over 300 of them. In addition, I have made the experience that often reported issues arise from Layer 8 problems. And that some issues, unfortunately, are not closed when they are outdated. Generally speaking and not related to this terminal emulator.
By the way, according to https://github.com/vim/vim/issues, the editor vim has over 1,300 issues. Also in this case, not all of them are actual problems that need to be fixed.
Yeah; if Gnome terminal had slightly better tab configuration it would be all the terminal I'd ever need, I think. Using it as an IDE (couple of Vim / YouCompleteMe tabs, a build tab, a unit test tab) is a bit of a finger twister to flip between.