Not sure it is going to have the effect that people think it will. This year and next year maybe, but then after that, not so much, in my opinion. The transfer rule is that you get a one time free pass to transfer. I could see the NCAA then basically not allowing exceptions for future transfers. In other words, once you have transferred once, you will have to sit out the next time regardless of your reason for transferring. I could also see them doing away with the grad transfer rule, claiming the new rule is the one free chance.
So, there are like 1500 players in the portal this year, and if all of them end up on new teams, that will be their one time free pass. Just for reference, that is an average of roughly 4.5 players per team. Now, less than 100 of those players will be leaving early from their new school for professional basketball. If they decide to transfer again, they will have to sit out. So this basically means you better be sure you are transferring to the right school when you transfer. So it might not hurt mid majors as much as people think. It will definitely have an impact the first couple of years, but after that, probably not. Even at that, most of the mid-majors that have a player worthy of moving up, that player is usually a junior or senior anyway. If you are a good player for a mid major, do you use your one free pass to transfer to Vandy, or do you stick around hoping you get good enough to go to UK, Duke, Kansas, etc. Because if you go to Vandy, that will basically eliminate you from moving any further up unless you are willing to sit out.
And the other side is this, that average of 4.5 players have to go somewhere. The better mid-major players may be moving up, but it is also likely that some players on the better program team are going to move down. At the end of the day, the amount of total roster spots are going to be the same, and the number of available players to fill those rosters will be the same. I am just not sure there will be quite the free for all after the first couple of years as we have seen the last couple years.