Yes your answer satisfies me shadowlord. It seems you have given it some thought. You would be surprised how few do.
If having a framework works for you that's fine by me. I don't need one but we are all different. I don't put cost above maximum flexibility. That is the main trade of between pre-booking and winging everything. In regards to whether a given RTW ticket price is a good price or not, as noted above the only way to know is for YOU to put together flight prices if you book each flight separately. No one can tell you if a given price is a good deal or not. The fact is that prices change daily. Trying to chase the lowest price is like chasing a stock on the stock market to buy on the lowest day. If anyone could figure that out they would be the world's richest person.
What I suggest is you decide what the maximum time and money you will have is. Then decide what part of the money you are willing to spend on transportation. Then look at what you can do with that amount of money. In other words, what will fit in your budget. If you can find a RTW price or collection of individual prices that will get you where you are interested in going and fits that budget then book it.
Simply put, rather than looking for the cheapest, just look for what you can afford. If you can afford it, buy it and forget about chasing the cheapest. You'll never find it anyway.