It doesn't "limit voting". No one is denied the right to vote because of the loss of straight-ticket. Sure the lines move slower, but that's a call to have more precincts, not to encourage partisanship.
The line moving slower, particularly in precincts where resources are already needlessly scarce, can dissuade others from voting. Further, what about people who just don't want to go through a huge ballot and vote on everything individually? That does happen. In fact, correct me if I am wrong, but doesn't Texas typically have a long ballot?
Under existing conditions, I think it would be false to say this doesn't limit voter access. Not everyone has the time or patience to wait, and it's not ok just because Republicans want to squeeze a few more votes for themselves.