I believe when we talk about Wieters a few things need to be remembered as we have this debate.
1. Most scouts had him as the top prospect in the draft this past summer
2. Most scouts think he is the best catcher in the last ten years(Mauer being the last)
3. He has the defensive skills to stay behind the plate(a plus defender whose arm has been clocked at 95 mph)
4. He is a special hitter so much so that he would have been a top pick if he played 3B, 1B, or OF
5. He is going to a team that needs him in the majors as soon as he is able
6. He has very good plate discipline
7. He has spent three years in college...which means he should be ready to produce by 2009
8. Nobody is a lock, but Clement is a comparable hitter but lacks the requsite defensive skills to succeed long term behind the plate and therefore may be better utilized at either 1B or DH.
All of the above are reasons why I believe that Wieters has a significantly better chance at succeeding at catcher than Clement. This is not to say that Clement may not be better, however when presented with other relevant information on the topic most scouts would take Wieters.