1) First of all, SCOTUS only invalidated section 4 of the voting rights act.
2) The majority opinion is that out of date criteria were used to extend the VRA for another 25 years.
3) The majority opinion also indicates that SCOTUS would tend to be willing to uphold section 4 of the VRA, if newer standards were applied, instead of the outdated ones. Now it's up to Congress to determine those new standards, if any.
It's a good ruling, and it doesn't step on the toes of Congress.