I'm an EXP and AUS-based most of the year. I think you're right on all counts. I have 8 flights this summer and booked them all in J because the fare difference between J and Y was not that large, which to me corroborates bullets 2-4. Also consider that the AUS-DFW routes are seeing the 321neos with 20J.

The LP scheme was always going to disadvantage those who only fly. It worked on me, as it got me to move spend non-travel spend to an AA-branded card, and YTD only 58% of my LPs this year are from flying. No way would I requal under the current scheme without the spend LPs.