Fedora is changing and it's no longer going to be the beast it once was going back to the Fedora Core days. Recently Fedora has been evolving under "Fedora.next" as various working groups for workstation, cloud, server, and other areas plot the future. There's talk of spinning Fedora into three distinct "products" for the workstation, cloud, and server. A lot still has to be decided by these working groups and FESCo, but some additional information can be found via the Fedora Project Wiki.
It's due in large part to these forthcoming fundamental changes that Fedora 21 won't be shipping before August to give Fedora developers more time to work on big ticket items and to try to decide what Fedora's future will behold.
Of course, not everyone is happy about this and its led to a fair amount of criticism. Yesterday an earlier Fedora.next discussion thread flared up again: Fedora.next in 2014 -- Big Picture and Themes.
That Fedora.next discussion was reignited by suggesting that Fedora 21 is released under the old approach to give the working groups more time to better plot the future and communicate the changes to the users/developers. The amount of bureaucracy and that the working group members weren't voted for also raised some issues.
Some are in support of delaying Fedora.next but still not doing the Fedora 21 release until at least August, since that release plan was already communicated to developers, but we'll see in the days ahead as this mailing list thread continues to erupt whether any changes will come as a result of the heated discussion.