That's fine, if you can afford to go BPA. That's not fine if you need to target positions in an already thin draft. If you drop to (just tossing out numbers as examples, not certainty for draft range) 10 and both available LTs get taken, you're boned if you needed an LT. And this draft not only just has the two "elite" prospects, it's thin on the next level prospects, too. In fact, I've seen multiple analyses that say that there aren't even 15 legit first round prospects in this draft.
That's why I'm asking the questions. Trading down is fine, theoretically. But, if the team finds itself needing to draft WR or LT, trading down my well end up meaning missing out.