The biggest problem in the secondary right now is Jimmy Smith. He got paid to be a top 10 CB and based off his play 2013-2104 it made a lot of sense. Unfortunately, his play is more in line with a bottom 10 CB than a top 10 CB.
I'm really hoping it's because he isn't 100% healthy and if that is the case, he will hopefully bounce back. I'd even consider sitting him a couple weeks or even IR if it means getting him back to what he was. Right now, he is not doing much positive.
Webb is pretty much what I expect him to be. He's solid in the slot, and that has value. Not what the Ravens are paying him, but he is still useful. I do think switching him strictly to a FS/slot CB role would help the defense.
Arrington is meh. Not terrible, but he can take some snaps in the slot and not be a complete liability.
Shareece Wright was awful in his first week but looked better vs Arizona. Too early to say much definitively. I don't think he is someone you count on moving forward.
All that said, I think drafting a CB high makes a lot of sense. Getting someone like Ramsey or Hargreaves could take a mediocre/poor group to a very good/elite one if Jimmy Smith bounces back, and if he doesn't you have a massive need at CB anyways.
Bosa would probably be my #1 choice, but I still doubt the Ravens get the #1 pick which is likely where Bosa goes. Tunsil is a very nice option at OT, but I think I would prioritize CB or pass rush over OL. WR might be an option as well depending on where the pick is.