Interesting debate........WW's heart, work ethic and quickness/elusiveness vs DJ's speed, talent, youth, potential and attitude.
Because of the known attitude that accompany's DJ I would tend to lean toward WW as he is the known commodity. DJ has more potential to be like a Randy Moss both in skill and attitude which can be very frustrating for a team and a fan base if the bad Randy/DJ comes out at the wrong time.
I personally think Wes is the better overall package at WR because he doesn't cause lockerroom issues. I would give up the up-side potential that comes with DJ for the stability that comes with Wes.
Note if simply looking at which player has the better overall skills associated with the WR position I believe that is DJ, however the rest of the package turns me off to him in favor of Wes.
just my 2 cents.