Greg Cox wrote:
Too many flaws and we would get a loser like Harry Kim.
Or, you could argue, Kim could have used a few more flaws just to make him more interesting!
Being a loser is the only flaw Kim has that matters. No other "flaw" will make him interesting to the people who hate losers. Not even Timeless will make up for that. The animus against identifying with losers is so powerful that people will hate Harry Kim despite the fact that he was a token who in seven years had maybe twice the episodes Reg Barclay got. Paris supposedly had flaws and was twice as boring in many times more episodes (much to the detriment of the Voyager series.)
And as a matter of fact the hero winning all the time is in fact quite satisfactory for quite a large number of people. It doesn't matter if the hero allows them to forgive themselves their favorite vices. That's merely a matter of personal taste and of no real interest.