Well,
I'd like to help you out here, not least as I'm currently tippy toeing around the idea of spending 800 odd Euro on a new wheel/pedal set up, an investment I'd like to see last way more than just a few months.
So, basically, the brouhaha that would be stirred up should Sony decide to kill off current peripherals by using a new proprietary mechanism is barely worth thinking about. It would be somewhat worse than very bad indeed.
I'll quickly get to the nitty gritty. From the images of the controller (microUSB port) and spec sheets that have been shown by Sony of the PS4, it's a virtual certainty that there'll be backward compatibility for USB'd devices.
Two distinct reasons for saying this are; USB3 being mentioned as socket of choice, remembering that USB2 works as it should in a USB3 port.
Secondly, running on an X86 architecture should alleviate any remaining issues for anyone who currently has a configuration that's PS3/PC compliant.
I'm as confident as is clinically allowed to say that there is almost no reason to think that there'd be a problem with the PS4 and current PS3/PC compatible wheel/pedal combinations.
I'm a bit confused as to why Fanatec would be faffing around waiting for confirmation of the PS4 spec sheet, seeing as how it has been released...
Hope this helps. 👍