Presumably, nearly all of those seniors would be eligible to do a grad transfer. Schools would either have unequal number of scholarships allowed or will have to make unexpected choices about how to fill out their rosters. You also need some justification for having a rule only apply to seniors, having it apply to players who maybe had one more game to play vs those who were already done with their season.
There are a lot of ramifications for the NCAA to consider. A snap decision under pressure now would be a big mistake. They couldnāt take it back.
One thing the NCAA has no control over, there are only so many minutes to go around. Some players are going to lose out whatever they decide.