1. Mike MacDonald has full control of the Baltimore Ravens defense
There is a real chance for plenty of the players to improve. Beyond that, there also is a chance that the defense gets a lot better scheme-wise. We have to remember that Mike MacDonald was coming from Michigan; it probably took him some time to get used to the NFL defensive calling.
However, like the Roquan Smith trade, you can see how things got better towards the end of the season. It helps when the team gets you better players, but those players are still here, so that will not change. What will change is that MacDonald is not only more equipped to call an NFL game, but he also knows his talent much better.
This year we may see him unleash Kyle Hamilton. Also, while Smith has a year to acclimate to the defense, MacDonald saw what he could do on the fly and now has a whole summer to draw up how to use him.
More than that, his defense is almost night and day compared to Wink Martindale. He ran a ton of zone and did not blitz, while Martindale loved to run man and loved to blitz. The players probably had some culture shock getting used to the new scheme as well.
So, Mike MacDonald is now more familiar with the skills of his players, and the players are now used to the scheme that MacDonald is running. As the two start to gel, the unit will grow. When you combine the scheme improving and the talent improving, the defense could be just as good as last year, if not better.