I’m likely to believe it a lot more now mainly because Apple has been hinting at it themselves.
Recent additions like the action button settings page, the sports and Invitations app and the recent photos redesign, as noted by others, don’t really fit into the iOS 7 design at all.
Also, the design changes that were being suggested last year for iOS 18 actually happened, the revamped control center and being able to place your icons anywhere were the two biggest rumors and those two things actually happened.
Also, Apple has slowly but surely been rolling out that frosted glass look throughout the rest of their operating systems, like the TV app sidebar.
I get that it’s pretty easy to dismiss all of this talk, but there is quite a bit of evidence pointing towards it being likely.
Apple hinting at anything means nothing! Look at Apple Siri 0.1 still operating on its last screw.