> Since the aim of query-replace-regexp is primarily to do a search
> and replace, not to find all places in the buffer where a regexp
> matches, it should instead skip over those cases and only ask about
> places where replacing will make a difference.

I don't think the difference is very important, but I wouldn't oppose
such a change.

Did you read the point I made above and which the reporter conceded, namely that such no-op replacements often indicate broken regexps?  Changing the behavior to either silently ignore such cases or issue a vague "skipped some replacements" message would make it more difficult to detect such breakage and the affected buffer locations, with the only benefit stated so far being to save someone typing "  +" instead of " +".