You do realize the Rams have one of the best secondaries in the league, right? If you were expecting huge games from Nelson or Cooper last night, that's not on them.
There was a reason Cook was so prevalent last night -- Gruden had the right playcalls in the first half by targeting weaknesses in their LB corps, and tried to leverage Richard in the same middle/underneath routes when the Rams adjusted.
That said, Carr looked horrendous -- having to account for Donald and Suh is hard enough, but even when there was little pressure, Carr looked really tentative and undisciplined and I absolutely would adjust expectations downwards accordingly for the Raiders passing game. I won't call them a dumpster fire based on Week 1, but I would not be depending on them for value unless this team begins to show they can right their ship.