Murph, while agreeing with many of his points, raised the issue of writer fatigue. It is a real issue. But then of Final Impact I was tired of that world and ready to leave. (I'm now ready to go back, after a break.)
For myself, I'd fear getting stale inside one world, even though with a whole world to build and explore that shouldn't be a issue. Perhaps Steve Stirling performed the trick best with his ISOT/DTF series, which effectively creates three narative realms out of one event. The Nantucket world, the post Change world, and the far post change world, all with their own character sets and story arcs.
I'm not sitting here planning my next five years. I have too much copy to get thru and quite a few of those years are allocated anyway. But I would be interested to see this topic discussed.