Of the replies, I'm going to respond to this one and spring off from there.
I see the point you're driving at, but I don't think the "dark" that many writers/artists are driving at are necessary to the Batman character, or even what people want. How many comics fans are truly pleased with the way Batman's been written for the past several years? I'm not saying there shouldn't be darkness, but Batman can still be dark without being a jerk. Comics can still be dark and have Robin in them. I don't know anyone who actually enjoys the excessive deaths and brooding that define Batman comics today.
Again, I'll point out that I'm not advocating for the recent comics version, and I'll agree with you that at times the "dark" in Dark Knight has been hamhandedly overwrought. I wouldn't call the last few years of comics Batman as any more right than this "sea of brightly colored children".
But that doesn't mean that moving away from "dark", "gritty", and most especially "noir" is the right direction for the character. It just means that skillful and nuanced writing is required.
For me, the definitive Batman was the first year of Batman: the Animated Series and the Mask of the Phantasm film. That Batman was dark, brooding, lonely, and scary just as Batman should be but managed to be all those things without being unsympathetic or unlikable. Moreover, the retro-deco stylings and noir sensibilities were absolutely perfect, and to me sorely missing in more recent years. They got it right.
Then, the suits decided it was skewing to too old of a demographic, and they wanted to kiddy it up. They mandated that Robin be in every episode, and that the writing be dumbed down and the tone lightened up. And to add insult to injury, they changed the name to The New Adventures of Batman and Robin. The series promptly jumped the shark.
Same thing happened when Joel Shumacher took over the Batman films. He brightened the color palette, lightened the tone and mood, and camped up the writing. And sure enough, he stuck Robin in there. Once again, it was shark jumping time, and no amount of Bat Shark Repellant was going to save it.
Starting to see a pattern here? That's what Robin DOES. That's the purpose of the character, to lighten the tone and give a more kid-friendly angle to the Batman property. That's why he was invented, and how he has been used time and time again ever since. The character is a walking bowdlerization in hotpants and fairy boots.
I could make quite a few more points, but that's the key here. Robin symbolizes the introduction of lighter, more kid-friendly elements to the Batman stories. That's what he's always done. And I cannot stand him. He's like Wesley Crusher, Jar Jar Binks and Scrappy Doo all rolled into one ball of brightly colored suck.