So DC is bringing back Wally West, and he's the same as the old Wally - except that he's black and has a new "street" backstory. Sure, the change adds character diversity, but how successful was the transition?
Bobby Joseph has a great write up on the topic at Bleeding Cool- I highly recommend you give it a read.
This highlights an on-going concern for modern comic book companies. In the early years, comic book heroes were almost always white, and predominantly male. There were a few notable exceptions - like Marvel's Mr. Wu - but for the most part non-white heroes were relegated to really unfortunate racial caricatures. See Marvel's Gypo, Whitwash or Slow-Motion Jones, or Fawcett Comic's Steamboat.
Compounding the problem is that the bullpin behind the scenes was often fairly diverse, as seen in this 1948 picture of the Marvel (then Timely) offices. We see Ray Hollaway (back left), Syd Shores (back right) and company.
Now there's a bigger push to have more diversity in comics, some of which has taken the form of old characters presented with new backgrounds, others with new characters filling old roles.
Some are successful (see Nick Fury), others not so much...
So now Flash is introducing a new take on Wally West that grew up on the streets, in and out of trouble with the law, and lacking a father-figure in his life.
A step in the right direction, or did the plan for diversity go off-track?