I'm not completely sure Ratliff would be more effective moving back to DE. I think Ratliff benefits from not having to face players with more latteral movement. Tie that with his great use of leverage (ie ability to clog the center) makes him a damn good NT. The ability to pass rush from the middle like a DE and the ability to clog the center like the big boys. I like Ratliff at NT.
Now don't take that the wrong way, I would like to see what he could do at DE today also which was why I was very happy with the Cowboys working Spears at NT.
Shall I waste time and show you 100+ plays of him completely dominating the hell out of teams attempting to run outside? You have one play, I can show you hundreds.