When iOS 7 is released not only will the Jailbreaking Community be busy working on finding vulnerabilities to create an Untethered Jailbreak around, but various frameworks required for tweaking and theming will need to be significantly overhauled to be compatible with the drastic changes Apple introduced in iOS 7.
Theming in particular could take a huge hit in iOS 7 as Saurik explained on a Reddit thread recently.
At this time, given that WinterBoard recieved no third-party help during all of iOS 6, I have very little hope in being able to support iOS 7. I need other people to tell me what to do to the engine: I am not a theme artist, I am just one of the few developers sympathetic to the needs of theme artists.
However, I operate in a vacuum: theme artists don’t talk to me, and when they do they almost never talk about WinterBoard’s theme engine: instead, they complain about how their theme isn’t getting enough exposure in Cydia, or about some UI element. The closest was king_of_hill in April, but almost everything he wanted were complex feature requests (and the key ones were already taken care of by “use Cydget instead of WinterBoard to do what you are doing: WinterBoard isn’t designed for that”).
What I need are concrete bug reports (with screenshots and exact filenames) and core theming help (such as information on artwork files, or “car files”, at the level of the loader). If iOS 7 is even themable at all, and assuming WinterBoard can’t already theme parts of it, it is likely that WinterBoard will never manage to support those components as I doubt seriously that after four years theme artists will start taking the engine seriously.
It appears as if theme creators just aren’t taking enough initiative to help WinterBoard progress and rather than trying to make WinterBoard better by contributing ideas and reporting bugs they just complain it isn’t good enough.
I wouldn’t say that theming will die forever with the introduction of iOS 7, but by the sounds of it, it will be a lot of work to port WinterBoard in particular to iOS 7.