You can criticize an entry I think without having to rewrite it yourself... Some people might not have the knowledge/time/will to do that (especially a full rewrite), but can still give valuable comments that others can use to improve the entry. I'd prefer either edit it or give comments above either edit it or shut up. Of course, going beyond "sucks" would be good. Maybe you can post your objections on the MCE entry's discussion page, Cooba?