Interesting post... while I would not say that the companion voucher scheme is perfect I've used them for annual holidays, flying club world to the following: Singapore, Hong Kong, Barbados, Vancouver, Bahrain, Peking (1st), Nashville, Austin, and up coming to Trinidad in November.
As for AmEx being accepted, I find it is widely accepted and purchase everything possible on it and clear it every month- even Lidl and Aldi 😉
My work diary is so restricted, I just look for flights and availability when I can, which means I travel to places I might not normally consider and that are not so popular. Average cost is around £1000-£1200 GBP which is usually cheaper than economy return fares to the same destination.