But is OneWorld always the best in terms of schedule, price and routing? I find that hard to believe, and I say that as someone who has been trying hard to fly exclusively OneWorld for Platinum status. Looking back at the bookings I made, sometimes Star Alliance was better in terms of routing (i.e. SYD > PIT via SFO versus SYD >PIT via DFW, Star Alliance) or in terms of pricing (i.e. SYD > FRA via SGN on VN being $300 cheaper with 1 less connection, SkyTeam).
That is crucial here. I mean if you can get status by taking a couple of flights you would ordinarily have to take anyways what do you have to lose? Try out the status and see if you like what you see. You might find it surprising. For instance, United beats Qantas hands down on seating perks. A United Gold member gets access to all seating options when booking, whereas with QF you must be Platinum One to get such a perk, and even then only on flights departing Australia. If you don't like United or Star Alliance, that's fine you have justification to your approach. But you'll never know what you're missing out on unless you give the competitors a fair shake.
But the key question is when you'll ever make use of that 3 bag allowance? 2 bags, sure I could see it, but the only people who would use 3 bags to my knowledge are people who move countries regularly like yours truly. I will also point out that some frequent flyer programs (i.e. United) offer 3 free checked bags for their mid-tier elites.
A QFF Gold can access any Flagship lounge so long as they are travelling on any OneWorld itinerary (including AA domestic).