Davis is an okay possession receiver... he's not that fast, and not that great. He belongs on a team, but as a #2 or #3. And for a team that frequently passes in the 150-220 yard per game range, that's not fantasy viable.
Lloyd has underperformed for his career. He's got better hands, better athletic ability, and a little better speed. But with a lot of this, it has more to do with play calling than anything else, because Orton isn't exactly surveying the field and choosing his best option... just doing what he's told, as of late.