I don't think I need to elaborate too much on my feelings with regards to Washington State, particularly at the current line where you are getting the better team with a plus sign.
But I think you have a situation where the WSU defensive strength of stopping the run, matches up well against the general MSU gameplan of running the ball for success. Michigan State was 109th in yards per pass attempt. So if the better than average WSU rush defense does its job, then I think MSU struggles to score. Washington State generated 8 more sacks on the year than did MSU (not too surprising) and have good speed to rush the passer. I don't see MSU throwing with a ton of success when Washinton State finished the year near the top of the pass defense stats while playing in a decent passing conference. Moreover, Washington State has largely played well vs this style of team, largely holding down USC, Stanford, and Colorado while allowing some large rushing yards to Washington. When WSU has the ball, they will be looking to throw a lot as their rush offense has disappeared as the season progressed and they are unlikely to have success vs the MSU rush defense. However, passing is their strength and pass defense is the MSU weakness. MSU didn't face many quality passing attacks this year and when they did they struggled a bit.
This seems like a cappers game to me. MSU will be popular but Washington State will win the game because, quite frankly, they are the better team and they match up well.
I would also point out there are some missing receivers for WSU but it is mitigated by the system they run, which I call a plug and play system.
This was an easy game to pull the trigger on for me. I am a little concerned about the horrible performances from the Pac12 so far but on paper this had to be played.