Thanks for the responses. RSW in Florida and ZAG or LJU, which are both equidistant to my hometown in Croatia. BA has a couple of flights a day from LHR to ZAG and there is also MAD to ZAG once a day on Iberia. It's really the lack of direct flights to RSW that kill it for me. There is a JetBlue code share that is direct, but my understanding is that you get no EQMs on AA. I'll call to confirm, but I've seen people mention this in FT.

I've had some frustrating UA experiences in the past--quite a few mechanical issues and unhelpful staff. And EWR can be a nightmare. Maybe my solution for now is to use UA to fly to RSW, which should get me to premier gold and E+ seating and focus the rest of my efforts on renewing AA plat. I unfortunately see no way of getting to exec plat this year with my work commitments.