I don't think that it is easy for any athlete to pick up WR or DB. Both are skill positions that require a good deal of position knowledge. The reason you see QBs move to WR is because of their familiarity and perspective with the routes - although you rarely see one do it well.
I do see a lot of high school QBs move to DB in college - I don't know exactly why that is but I seem to see it a lot.
I think the cornerback-proposal is very far-fetched as well. If Webb can tackle well then safety would be a better option than corner, but I doubt he's a good tackler.
As for the receiver vs. corner argument: Playing cornerback takes years and years of practice because the receiver is dictating everything. A corner has to recognize and react while a receiver is more of "his own boss". In my opinion, cornerback and quarterback are two of the most difficult positions in the NFL.
I have practically not seen enough of Joe Webb in the receiver role to make a proper judgment on whether he can play the position or not, but outside QB, I think WR and read-option QB are his best positions. However, lets not forget the special teams. He could be a good returner or gunner.
But to say that's why most guys who are recruited as "athletes" don't become corners isn't true. Most position changes happen in college, typically early on. I think it has more to do with placing a value on scoring more so than coverage. Coaches want to get the ball into the hands of their best athletes. Obviously it's important to have good cover guys, especially in the NFL, but in college a guy who can score is more valuable.
I like this move. Glad they are still giving him a chance rather than just canning him. I don't see why he couldn't be a successful wideout. He's obviously very athletic and has shown he can make plays. He should have never been at the qb position in the first place IMO.
Joe Webb has great size with long arms and explosivity and speed. By just comparing his combination of size and athleticism with others receivers we might have the best wide receiver in the league. But the most important factors are still in question: route-running and catching abilities.
I also have the impression that if quarterbacks aren't moved to WR, they are moved to free safety. This could be that the safety are in some ways the "quarterback" of the defense as they have to read the opposite team and react to various aspects.
.. but there are exceptions. Our own Erin Henderson moved from quarterback to linebacker. Seahawks' Michael Robinson moved from quarterback to fullback.
To be a WR you need to be able to run correct routes and you have to have great hands. You need neither to be a CB. I never said CB was easy but as a general rule guys that can catch the ball and run routes get to be WR's and the ones that don't have the talent- well, the coach makes them a DB.Of course they get a little testy when someone points it out.
While what you say is true about the transition from QB to WR that is because QB is much harder to excel at the NFL level than WR. But by the same token, how many college CB's do you see switched to WR if it is easier to learn than CB?
I don't think either position change is realistic without previous experience (QB to WR vs. QB to CB), especially at the NFL level.
Joe Webb is 6-4. If he was put in at corner, he would be the tallest guy to every play that position in the NFL. Ok, I don't know if that is true, but I can't think of anyone that tall to ever play corner. Sherman is probably close. Asking him to backpedal, move his hips, stop and change directions,... probably not going to be real natural for him.
Safety probably easier, as he can play going forward more and his knowledge of the game as a QB should make it easier for him to understand coverages. His speed and range would be a big asset, but he also needs to be willing to lower his shoulder (head up of course :)) and lay the wood. Best fit probably in the prevent where you ask him to protect deep.
In the case of Joe Webb, I would say that WR would be an easier fit with his skillset and body type. Not a polished route running WR, but a deep threat with his speed and height...that is if he can catch. You could always toss it down the line of scrimmage to him, run reverses or screens and let him do his thing in space as well.
I think DB is out of the question here. Not because he doesn't have the ability, but you have to realize that DBs need to be FAST and QUICK. Not just relatively fast, but a DB should be one of themost athletic guys on the field.
Webb, although athletic, is good as a Quarterback. Compare him to a WR, RB and DB, and he's just so-so. He's not faster than the top Corners in the league, and he's certainly not quicker. He's not elite in the NFL with any of his measurables (maybe jumping). And I honestly don't think he can react quick enough and keep up with the top receivers. He might be a servicable #5 DB, but that's about it.
I really don't think Webb has a place in the NFL. I just don't. I thought he might turn into an ok backup QB , but that's not the case.