Yes, for example VLC doesn't support v4l2 yet.
Here is a patch I back ported to 2.6.17 last year.
http://www.pixelbeat.org/patches/linux-2.6.17-em28xx-v4l1.diff
I didn't try to get it merged as I thought Markus would do it,
but looks like that's unlikely now.
Also here is a patch to allow shared access to the video device
(so you can have a separate tuner program to VLC for example):
http://www.pixelbeat.org/patches/linux-2.6.17-em28xx-shared.diff
It is necessary if Markus wants to stop people merging code back from
his in-kernel driver fork. Call me a cynic, but I'm confused about Markus'
motives in all this.
Markus, please do the right thing and just merge your code!
(and please don't reply this giving reasons you won't/can't do this).
Pádraig.
-