#4 Add some variety to the main roster

The biggest problem with WWE's main roster is that the matchmaking tends to get repeated and stale throughout a few weeks. If you remember, we just saw Braun Strowman taking on Baron Corbin at the Elimination Chamber 2019 in a No DQ match.
Within 24 hours, we saw yet another match between these two superstars - this time in a table match. None of these matches were above mediocre - so we can't compare them with matches like Stone Cold vs Rock - which happened more than a few times, yet managed to grab our attention.
Introducing four new members into the main roster will certainly help to freshen things up a bit. However, we also need to keep in mind that WWE is doing nothing with other call ups like EC3.