I don't think they're a weakness, just not the strength we thought they'd be. LBs are still the #1 concern, although we'll see if Styles can take this production against bad teams and use it to be more confident and productive in big games. Glad they're using him on blitzes more and more.
Can't say anything we've seen with Igbinosun is surprising. He's always been too grabby and not the greatest cover corner, but is good much more often than not and is a very willing run defender. Not sure what the issue is with Burke. Even Matthews seems to have regressed a bit.
Defense overall has been weird this year. Maybe they've tried to do too much behind the scenes and it's made it difficult for the players to get comfortable, especially in the back 7. They started out vanilla, but since Oregon have used different types of coverage, blitzes, and even a different alignment with a Jack against Purdue. Can't imagine they installed much of this in the middle of the season, so it's a lot of things to keep in mind even for a bunch of seniors. Here's hoping they'll pare down the playbook next season and focus on more of what worked in the backhalf of this season.