Wouldn't you agree that the writters made Heisenberg's meth blue so the viewer and DEA can follow his product with ease so it doesn't get mixed with the others? Alot of people say "ooohh!! In real life it wouldn't be blue!!" well that's just Holly Wood..
No. You rarely see other meth during the show, and never side-by-side with Walt's meth. If anything, it's for originality in the real world. Any time you see a baggie with blue crystals (or even other "unconventional" colors), people will think of Breaking Bad.
And is Walt's "baby blue" his meth, or the person who he made the meth for, Skyler - who dresses primarily in blue? Symbolism is a whole other beast to tackle, and is one of the reasons why Breaking Bad is so re-watchable.