Justin Houston makes a lot of sense. They brought him in, and a post draft signing looked like a decent bet. Maybe they are waiting until June 1...which leads me to the receiver part of your post. I like the the WR coaches we have now, and the talent/range of skills of the players on the roster. Watkins is the old man at 27 lol. But- that Julio Jones rumor just wont go away. I really don't see a deal happening, but maybe that partly explains why they haven't signed Houston? Probably no way they can have both. A jones deal is likely dead if the asking price is still a first rounder, plus the cap hit is problematic with possible contract extensions of key players looming.
I think the Ravens are ready to go with what they have. The secondary is super deep, and Wink will have creative blitz packages, so a proven 10 sack guy on the edge is not a must. They probably have one or 2 on the roster that are ready to be that guy anyway.