You're right on all counts. Nothing in this industry beats seniority. Nothing in this industry impacts your quality of life more than your ability to bid for schedules, hold the equipment you want, base you want, vacation you want. Also for second career (ie older than the early to mid-twenties guys who are just starting out a first career) getting in sooner to capitalize on the direct contribution for retirement is HUGE. When you have 40 years or so to compound the interest of a 401k, you've got time to build a base...discounting any previous retirement package, comparing just what you will have from an airline career of 25 years at a major with 16% direct contribution, vs 40+ years, the difference can be staggering. Also with the wave of hiring catching guys in their 20s for the majors (having many friends still at the majors, they've all commented that many of the newhires are coming from 1-3 year FOs at regionals and are still in their 20s), the guys hired ahead of you may be considerably younger and thus won't drop off the seniority list before you do.

There are so many reasons to get to the final destination as soon as possible, you're making the right move. For end-of-career guys like me who've already been there, and only came back to work to kill the last couple of years and make a little more money, it's not important. We can ride out moving up the list here (I've moved up 400 numbers in the 9 months since I started, and have 400+ guys below me as well,) take our 4 weeks of vacation starting next year, and have some fun flying with younger guys who haven't lost a small piece of their soul to the frustrations that lead to burn out in this business.

Good luck at SWA. Even if it ends up not being the place you want to spend the rest of your career, it will open doors at every other major out there.... and as someone else pointed out here, there is the possibility of leveraging the class date with AA to get hired if you know someone in recruiting. You never know until you try.