Transfer rules are fair for the individual - they should be able to transfer as many times as they want.
But the portal shouldn't open up until Mid April and should remain open until August. That will prevent guys from transferring during the season. Well it won't happen as often. Plus, if they go through spring practice maybe they'll decide to stay.
Incoming transfers will only have fall practice to prepare for the season.
I think if you do this you won't have as many transfers.