Not sure why you needed to post two threads?

AA and QR are both one world airlines as you know, so nothing is stopping you keeping your AA account and crediting any QR flights there. Given you already have status this would be my personal choice but it depends on how much you travel home and whether you can meet the specific requirements to maintain status.

You've identified a lot of airline-specific reasons that shouldn't really relate to a decision on FF. "Lots of non-stop options from Doha" is an airline thing and not in itself a reason to change FF program, similarly the point you mention as a con that "Qatar is quite expensive" is also an airline thing. It seems the only reason you have identified as a pro is the upgrades, which again aren't a reason I would personally throw away the AA program.

Good luck with your decision and your new job!