Maybe emacs' level of brokenness is comparable to other editors, but it's far short of the ideal of problem-free software -- it suffers from all kinds of little bugs because of weird package interactions.
E.g., there's a mode to edit grep results, and a mode to edit multiple occurrences of a symbol inline, but using these two modes together doesn't work, for some reason. There's a mode to highlight the current line, and a mode to run a shell inside emacs, but highlighting the current line doesn't work on the most-recent line of the shell, for some reason. Highlighting the current line also doesn't work when jumping to compile errors (for me, anyway) -- that last one particularly frustrating since jumping to a compile error is one of the times you want line-highlighting most...
Etc etc etc.
Have you started playing with strategies to proactively identify potential clashes?
I think one of the big challenges will be establishing the best practices for plug-ins to avoid user-experience-ruining clashes.
[1] - I help maintain the smooth-scrolling minor-mode and diagnosing and solving some of the interactions with evil-mode and macros has been... fun. Thankfully the Emacs community is populated by people who provide excellent bug reports!