Word but there are issues with making it rigid.
Last year the Celtics had the best team. You can make an argument that neither Tatum or Brown were top 5 players in the league. Giving one of them MVP would have been wrong.
The way it is right now, there is unofficial criteria. The first thing is to make sure the team with the MVP is a top seed, but because it's unofficial, when something historic happens like Westbrook averaging a triple double, they can still give it to him even though his team is the 8th seed.
Imo this isn't a bad way to do it. Have guidelines and unofficial criteria, but because it's unofficial, you can go outside that criteria when something happens that gives you reason to go around that criteria.