I believe RTWs are one of the most flexible ways of traveling in premium classes for a reasonable amount of money.
If you really plan to change your routing several times mid drip this becomes costly and time consuming. I am using a lot of RTWs and usually have more then one open.
My strategy is: When i know the first part of a trip (say Asia to US) i book the ticket with the flights i want and the routing i need. The rest of the ticket is just for dummy flights and dummy dates. Then wen i need the ticket from US to Europe the next routing change and the third routing change for the last part of the trip.
I buy my tickets from a TA who knows what he is doing. Whenever i need changes i email him and he does everything for me. No need to spend time on the phone with airlines, wait at ticket counters. He charges a fee, but it is well worth it.
For that reason i also need electronic tickets, because then rerouting and ticket reissues are possible via email.

This strategy possibly does not make sense for somebody who is budget constrained on an economy ticket, because often there are cheaper ways in economy.
But traveling in F and repositioning one to one of the cheap starting points makes this a very flexible, convenient and inexpensive (for F) way of travel.