I really don't think that WN will make a move on the Alaska Air Group any time soon. First of all, only a small portion of the AS fleet is common with WN. I know - they both fly nothing but 737's, but WN flies the 300, 500, and 700, AS flies the 400, 700, 800, and 900. You may say "big deal" they are still 737's. The problem is, with the general seating that WN uses, there is no way to keep track of how many people are sitting in what part of the airplane (they would have to go through and count before each departure - doesn't help the quick turn very much). Not a big deal on the shorter 300, 500, and 700; they are all one seating zone for weight and balance purposes, but the longer 400, 800, and 900's (the majority of the AS fleet) have multiple seating zones that must be used for W & B calculations (my wife was an AS load planner - many horror stories about trying to balance the 900). I also think that WN would want nothing to do with a big chunk of the AS operation (ie. the state of Alaska - and I don't mean ANC or FAI).
Also, for its size - the Air Group is a pretty cash strong carrier. A takeover purchase would not come cheep. In my mind, these things, along with the "poison pill" make AS an unlikely target for WN.
I think our code share is safe for a while
I think AS would be a great fit for DL though.