Rather than to try to move your loyalty somewhere unknown, I'd suggest kayaking for a bit either 50% (balance on UA) or 100%:
- Shop around for discount J or PE on your longhauls.
- Fly domestic on whatever non-ULCC has the best combination of cabin/price/schedule for each trip.

I've cut my UA travel by a third to a half in the last year and it's working out great. I fly UA just enough to make gold since I find the perks worthwhile (primarily *G & complimentary E+), and since I'm Houston based it doesn't really make sense to switch that to one of the other majors. On the whole I probably spend a bit more money, spend less time flying/in airports, and I'm happier with the products I get especially knowing I can change it at any time if I become unhappy with an airline/product/pricing strategy. There's something mentally liberating there compared to trying to be consistent with one airline. The airlines want to half-play this transactional game, and it's working for me to play it with them.