Fly AA for DFW-NRT-BKK
If you are making 4-5 trips to BKK each year, this would put you very near top status on AA. As an EXP you should have little problem upgrading the NRT-BKK leg (the long leg). The BIZ seats on NRT-BKK (some JAL metal) just seem like economy plus, but a little more leg room.
Also, as EXP you get 8 free upgrades which saves you the co-pay and miles. I've only missed one upgrade in 5 years of flights to BKK.
It's an option. Good luck to you.