I think your hunch is right on the money, Jetstream. Williams is near the top of the Cardinals' draft, no question. I believe they have him rated as the number one or number two defensive lineman with Dewayne Robertson.
Williams won't get past Seattle at #11. Either the Cardinals trade down to #9 or #10...or they stay put and take him. Robertson more than likely will be a top five pick, so the Cardinals' decision could come down to Suggs or Williams...and it's entirely possible that Jimmy Kennedy, if he gets by Dallas will be on the board as well. So there the Cardinals will be...deciding between Williams, Suggs or Kennedy. Trading down a couple of spots becomes very attractive in this scenario because one of the three will still be there. However, how likely is it that the Vikings, Jaguars, Panthers or Ravens will trade up to #6? I would say slim to none. The possible suitors are more likely to be the Jets, Patriots or Saints...at #13, #14, #17 respectively. Williams will almost certainly be taken before #13. In fact, if he does somehow get by Seatlle at #11, St. Louis, another NFC West rival, could scoop him up at #12.
Therefore, we shouldn't be surprised if the Cardinals select Williams at #6 if they can't trade down two to four spots. This will have Mel Kiper in an uproar, because Mel is all about value and Mel won't think that Kevin Williams is a top ten value, let alone at #6. I can just hear Mel now..."Typical Cardinals...they don't understand draft value."