What I'm hearing from you is that trading up for "a monster DE" is worth it. Honestly, I mean no disrespect, but does the 2005 draft even have "a monster DE or WR" that's worth trading both picks for?? If it were a Reggie White, Bruce Smith, Julius Peppers, type of player, then yes! But from the reviews this year, it doesn't seem there's anyone that fits that mold. No DE is close to being ranked as that type of player.
That's how a team hurts itself, by fixating on a need and blindly trading up for it. You have to gauge the draft, and see what is available. If Dallas' only need was DE, then I'd say yes, but Dallas has several holes to fill, as do most teams.
As far as trading up for a WR, does Dallas really need one that badly? I, for one, am curious to see how far Mike Williams will fall. That's why I would think long and hard before trading up for him or Braylon Edwards. Both have the same potential, and MW will probably fall. I'd gamble on the one whose "draft stock" fell a little bit on Day one.