Actually I flew one of the traditional majors for years, and had maintained Platinum (2nd highest) status rating. My main reason for flying them was the upgrades which gave me a more comfortable seat, and the ability to actually get some work done.

With all the consolidations, my upgrade percentage dropped from around 90% to down in the 30-35% range over the past few years. Also, because I was flying "last minute", seat selection in coach was often middle seats or last row options.

I have shifted the majority of my flying to WN this year. The driving factor in the change was the lower fares I am getting a vast majority of the time. We are a small business, and I can't afford to be spending upwards of $1k for a domestic flight.

The side benefit of the change is that while I am not getting upgrades, I am absolutely getting a good seat 99% of the time since I made A-List. Yes, it's in economy, but the seat pitch is better than what I was flying, and while I can't easily work, at least I arrive in good spirits. I will take that over 30% upgrades and 60% bad seat any time.

So, if WN were to offer a true business class it would depend on how they did it. If they left things as today, no reserved seats, but 1-15 (or 1-16 probably) had BC seats and the rest in back, that would work fine. The challenge would be for the FAs in making sure people in back didn't just decide to sit up front. They could even offer upgrades to A-Listers who were 16 - ? if BC was not filled. While that would be nice, I would rather they focus on maintaining a good flight experience, low fares, and usually (for me) on time flights. I'll give up the BC to always get a good seat.