Re-sending a rejected paper to the same conference next year
I would not recommend stating that it's a revised paper for several reasons:


Contrary to your assumption, it is not likely to be reviewed by the same people.  Typically, each topic in a large computer science conference may be covered by many reviewers, and they get assigned either arbitrarily or by a bidding process.  With a few reviewers assigned from a large pool, there might or might not be overlap, but the majority will likely not have seen the prior version.
Computer science conferences, unlike journals, do not tend to provide a "comments to reviewers" section in their submissions.  Trying to wedge that in will likely make your submission stand out in a bad way, putting the idea of rejection in your reviewers' heads.
If you've really done a strong set of revisions, it should be pretty obvious that the paper has changed a lot even to a reviewer who's seen it before.


In short: I see no particular positives and several negatives for such a declaration.