There are a number of things the NCAA could do, but I cannot imagine a lawsuit by SAs being beneficial to college basketball. Or, at least, solving the problems with money or one and dones.
What could be done:
1- Require all freshmen in football and basketball to take a redshirt season in their first year.
2- Establish an academic scorecard for every SA that is guaranteed for five years. Or less if the SA graduates. If the SA drops out of school (or the team) for any reason other than graduation or career ending injury, the athletic department cannot reuse that scholarship until the academic scorecard also runs its course.
3- If a SA transfers to another college, his scorecard transfers with him.
4- When a college makes an offer to a potential SA, the SA can sign the offer sheet at any time he wishes. No non-commit-able offers or grayshirts allowed. A college can withdraw the offer at any time before the SA signs it. Once signed, it cannot be withdrawn.