If Dems get this pick, Sri Srivasen will restore the voting rights act which will hurt the GOP, especially in 2017-2018 whenvoting drops among Dems. Nevertheless its a setback for concealed weapons carry and campaign finance reform on the part of conservatives.
It's not like a new majority can just vote to change existing precedent. There has to be an actual case involving Sec. 4 of the VRA, which cannot happen until Congress acts because lower courts will apply stare decisis in the meantime, and stare decisis says that the Sec. 4 formula is unconstitutional as of 2013. Ditto with campaign finance restrictions under BCRA. Yes, a 5-4 lib majority will likely uphold future laws equivalent to those struck down by the conservative majority, but that still requires Congress to make the new law in the first place. And that's not going to happen during the next 2 years. Assuming the Dems take both Houses of Congress and the Presidency in 2016, and also assuming that they somehow manage to force through a magical new VRA formula for preclearance in about a year, it would still only apply prospectively, which does nada for maps already in existence in 2018.
On guns you are right about concealed carry, although I'm actually relieved now that cert. was not granted on the assault weapons case. This term is going to be an abysmal minefield of dysfunctional 4-4 cases. Scalia's death will negatively impact the legal field for a generation because of the unsatisfactory non-precedential decisions.