Thats a very polarized question, but I ask it myself for my stories. so far I think : Who wants to read a story of a depressed boy longing for sex, getting nothing, getting no progress, having no idea, being really a "looser" with no hope with the story ending that there is no progress, no hope , not anything ? barely anyone. unless they enjoy his or her suffering or enjoy the madness of a Lars von Trier (and that will be never popular I think).
But many enjoy seeing people with problems (or such depressed clichees) getting into trouble and through that (alone or with friends) becoming something new. The classic Quest of Odysseus proofs it just keeps being interested to fight something that seems too big to be beaten, like hydras and zyklops, nowadays it might be the sense of no deaper meaning, superstructures like government and industries (like in nihei's stories etc) or just plain apocalypse (zombies). Interesting to note that there is a big longing for nonsense too now. stuff like lucky star - no loosers, no winners at all. just enjoying life.
I think "perfect" winners are funny when its used in comedy like in bastard. I mean, basically he is a winner. But he is designed to be childish and so egoistical that it becomes a joke, and hence, interesting. But yeah, many people may deny it, but series like buffy and angel are successful, because the struggle part doesnt reduce their "winner" looks , there are so many boring vampire loverstories on the market, its frightening, and it sells.
ohhh he is undead, he might be weak, but overall he is winning, charming and gets laid everyone.. but has no interest because he is so cool and the womenz go swooooon. go figure
As long as the hero struggles, it doesnt matter so much from which area he or she comes. people just really hope for a happy end, or , as I see it, at least a glimps of hope in these days, where happy ends seem .. fake.
Its a little bit like the clichee going when there are bad financial times, people long for vampires and zombies. o-O
Also notable : heroics in connection with the power of friends. bleach and naruto is all you need to notice , people love to be part of a big success. The hero can be a looser or a womanizer , it doesnt matter in that model. More attractive example might be persona 4, but to each person his shoe..
Another model i notice in niheis work for example is that the focus shifts more to the general disastrous but interesting development of the world, making the person a struggling hero, but not a worldsaver per se, makes it identifiable for a more grown up readers area.
I think its more important to connect the style and your personal interests with a desireable option.
Would blame work with pokemon optics ? I doubt it. Unless you add friends.
Nobody wants to ear the story of some guy that always wins and has a great life. We mostly wanna ear about the guy that struggle to get to the top. Cuz, let's face it, life isn't easy and we all need to learn a bit from someone else experience... at one point or another, we are all losers trying to be winners.
A compelling character is a character that we can relate to. Losers and nobodies because they have the challenges of overcoming their fears and difficulties. While protagonists that are already winners have nothing to challenge them.
I had to choose one, but I'd say it goes both ways.
A winner has to get over himself. A loser has to get over the obstacles.
The best points of both, A winner reminds you of the person you dreamed you could be (eg. thor, tony stark). A loser reminds you of yourself and/or reality (eg. naruto[season1], peter griffin, )
Challenges Balancing a winner's strength against the odds. (if no circumstance can touch them, it's not much of a story) Balancing a character's integrity while in trying situations. (basically keeping them from looking weak or spineless)