If you start measuring some metric, the team will adapt at improving that metric, but inevitably this will spill out into distorting or lowering performance in some other aspect. So as you point out, such survivor board might make team focus on fixing trivial/easy issues, but the issues requiring big time investment might go unfixed (as it would make 10 trivial issues pile up while you fix 1 old hard ticket - which will make you look bad).

Just make sure this is what you want.