Need suggestions for best overall experience
 

First time doing RTW, never flown QF or CX or BA before.

Flying in business, AA PLT.

DFW - LAS
LAS - BKK
BKK - NRT
NRT - SYD
SYD - DFW

Have prices for Circle Pacific and OWE4. Any advantages to coming back through, say, LHR instead of straight back?

Looking for ideas on best routing and best flight experience, especially if I'm can use miles on AA segments to upgrade to first.

The OWE is not mileage based but segment based (20 segs total, 4 per continent except 6 in North America), while the Circle fares are mileage based and you are likely to have some difficulty in keeping within the mileage limit for your proposed routing. You can get about 50% more miles for the same price using the OWE fare; the "drawback" is that you must fly around the world. The 6 NA segments could be used for 2 additional trips (DFW-LAX for example), which might make it worth considerably more for you (D books into first class on AA flights, and into Y on Eagle).

Reminder/correction -- you don't get 6 N. America segments if purchasing tix/originating in N. Amer. You only get 2 stopovers.

Well, to be absolutely precise, you DO get six segments, but you may only have two stopovers. Which means that some of those segments will almost certainly have to be mileage runs. Remember also that you cannot return to the originating point before the last segment of the ticket.

Doesn't matter now
 

Looks like the want me to do this in an order that eliminates any RTW possibility:

DFW - LAS - BKK - SYD - NRT - DFW

Guess I'll get a JAL bonus and can use miles to upgrade to F on the trans-pac flights though.