Those that play on a casual basis can continue to do so, with the amount of accessible content increased.
Those that enjoy overcoming new challenges on a planned schedule with a strong team can continue to do so, with a change of scenery and new fights to learn.

Those that thought that putting in a few months work to clear all the current would earn them fame and adoration, now and forever... well they may have just tasted the hard, salty shaft of reality thrusting through their delusions. You want fame and adoration, perhaps there is perhaps some to be had from clearing the new turns first, or very early on your server. 6-9 will be a new chance for that world first!

All in all, I don't really see any valid complaints about turn 1-5 going on DF. And to be quite honest, it's still not going to be walk in the park, organised FCs will still be the best option for successful filling in those missing slots or gearing alts to ilvl90.