Um.....if the point of "creative" is to "create" then the additional features have less value to creative players.
not everyone wants to start at a falt landscape, some players get inspired for their stuff by the landscape thats already there and some settings could bring interesting stuff to them
Edit: forgot the quote
I see no new 14w17b to fix the numerous bugs of this 14w17a, so I'll need to wait till a new snapshot to update my server, too much bugs in that 14w17a, but at least they reverted their awesome and stupid (yes both at the same time) new Minecart physics, for some parts, its really awesome, but for the numerous problems like not being able to climb a slope at all even if fully made of booster rails is quite nerve racking to be honest, at least I hope they keep the new behavior of the activator track which was pretty useless its now awesome, automatically getting out of the minecart at the proper place, now they need a way to make a boarding track like in Railcraft and that would be complete.
Hmm, I tried to make a customized world with very few changes just to see how it works, and it got stuck at building terrain. Although it seems after it crashed, I loaded it back and the world spawned fine..so..Just the original world creation crashed, but the world still worked. Weird.
Also, this customization is awesome but I gotta figure it out. I barely changed anything and I have a weird lookin world. Maybe it got corrupted or something because it crashed the first time, but it looks kinda cool.