It seems to me only depth is needed according to Moon Mullin. According to the article Pace is satisfied with Houston and his 8 sacks last year according to this:
And maybe I was wrong about Ferguson too. Looks like the Bears are counting on him for at least depth. I still believe that the Bears go 3/4 DE in the draft at #11. I could even see a slight tradedown. I don't envision a tradedown with say Denver at the bottom of the 1st or trade out of the 1st.