robin is an access point to a lot of the batman titles. kids can't always associate with batman, but they could associate with robin -- closer to their age, and a more attainable, belieavable persona / ability level. a kid wouldn't necessarily think "i have to beat up killer croc, and rescue that orphan before he's murdered," but he might think "wow, batman is so cool, especially when he beat up killer croc and saved that kid! ... and i got to help!!"
its also, as expressed by time sale and bruce timm, amongst others, a great contrast, visually, to batman. batman looks like a big, dark badass -- put plop him next to a wee lil kid in bright colors and, bam, he's scarier times ten!
personally, i'm not muchuva fan, unless its done in small doses.
and, really, the only perspective i like is that of robin being a low-ranking soldier in training. i.e; what batman says is law, no questions, ever. carrie kelly was a great example of that, as was the animated tim drake.
i also prefer the animated tim drake's costume -- a much darker tone of colors, and limited to a robin's red (with some yellow thrown in)
