I think the best play is to resort to default strategy vs arsenal because that has yielded wins (which is needed). Just because you need a win doesn't mean we should allow it to be more open. Having said that, Arsenal are different now - more unpredictable (in a good way) in how they set up and they may just sit deep like duck says and Walcott makes sense.
We do need to win to keep slim league hopes alive (top 4 not concerned) and nothing has been encouraging so far - I expect the team to get back to a high level at some point and I don't want to be that fan that says 'if the league started on x date we'd be in y position'. Cech throwing a couple in would help for the time being until things get back to normal.
I worry that mourinho just gonna dangle the "here have possession" carrot and arsene/arsenal will be unable to resist being more attacking. That said they dealt with this pretty well in the game at the emirates last year. Also I think arsenal will be able to press well if they lose the ball with a high defensive line unlike years past if they start Gabriel/kosc. The threat of Walcott running into space will make it tough for Chelsea to compact the field and clog up the center like they normally do.
The biggest difference between this Chelsea and last year's is they've been horrendous at limiting passes and shots in central areas in front of goal. They are averaging 7.8 shots on target against per game! Even west Brom got 6 on target vs them. Pulis has only done that once ever with Brom... Vs qpr!
Chelsea have allowed so, so, so much space in the midfield against much worse teams than Arsenal and Ivanovic has been destroyed by players much worse than Sanchez. Those are our likely routes to getting a point/winning.
Hazard and Sanchez could both do with a goal for confidence, but Sanchez has the most shots attempted in the top 5 leagues without one while Hazard has 6 shots for .5 xG.