Must not: #4 Seth Rollins

Seth Rollins defeated Brock Lesnar for the Universal Championship at WrestleMania 35. A feat that very few men have been able to achieve.
The win means that he's in the driver's seat as far as the red brand is concerned, and will have to shoulder the responsibility of carrying the brand forward. And this is why we think that he should still be on RAW after the Superstar Shakeup.
WWE might want to shake things up big-time, making the overall draft feel really meaningful. Rollins is one superstar that they should leave alone for a bit.
He's won the title after a long time and will have the chance to deliver a number of great feuds as a full-time Universal Champion, burning it down every week.
Fortunately, it's unlikely that WWE will move the Beastslayer to the blue brand, but you never know in WWE.