Don't be put off by posts complaining about difficulties in getting reservations on particular flights. We rarely hear what kind of advance notice was given or what research was carried out about availability on a given segment. We do hear of many successful xONEx trips, including FTers coping with multiple nested xONExs! (I might regret saying this when trying to get my A-class seat on CX from NRT to HKG, but we'll see.)

Assuming you intend to firm-up on your itinerary a month or so in advance, and are willing to be a bit flexible over exact dates, you should be fine for the great majority of RTW itineraries. Sure, there are one or two routes of which you need to be careful, JNB-SYD (or v/v) in D is one, but plenty of people who contribute to this forum can point these out. My recommendation is to play with the really great MileageMonkey tool & then post your draft itinerary here. The RTW gurus will then gather & give you a pile of comments. It's then up to you to sort the wheat from the chaff.