Hi all... thanks to this board, I'm part way through an AONE6 booked and paid for in MRU. Great advice thanks!

I keep having to change the dates as I have had to come out of the itinerary to come back to europe twice now for work reasons..
this is the original itinerary
MRU-JNB-LHR-MIA-EZE- (all flown ^)
this is what remains as currently booked
EZE-SCL-GRU-JFK-DFW-MEX-DFW-YVR-DFW-LAX-SYD-AKL-HKG-BOM-LHR-NBO
I'm not sure I'm making best use of 'genuine' F class (in terms of maximum mies, TPs and of course comfort!) and my needs have changed a bit in that I only want to visit DFW once, and I would like to include NRT if possible.
The order of destinations is not important.
Do any of you experts have any advice for me? Your creativity and lateral thinking would be MUCH appreciated!
A reply on the BA forum to another question alerted me to the possibility of a better routing for this ticket...
I have a paper ticket, but I guess I could pay a re-route charge at LHR which I pass through frequently - which would be a one-off even if I changed several sectors?
THANKS!
HL