Can someone do this with a really new Lens? (70-200 2.8 II or 24-70 II)?
There was a Rumor that Canon changed Autofocus algorithms and Focus is now checked after focussing and corrected if not perfect (u can see this when the Lens does a tiny step after the first fast and large one). But it works only with new Lenses and Cameras (rumor said so)
Yes, it's still useful. The newer lenses combined with newer bodies tend to have better AF consistency, but in terms of actual focus accuracy MFA can still improve things since you can still have a mis-match between what the actual focus is, and what the AF sensor says it is.