This has already been discuss multiple times, even this week there was some talk about it.
The EVF has still a long way to go and it would mean that Pentax also need to bring out new lenses to take advantage of the mirror less camera and I don't see Pentax currently able to support 3 lens line up.

Looks like thread to me link but I can be wrong.

I had a quick look when you mention it John, didn't saw that it was so complex
A simple turn and click like a hood looks like it should be enough. At least I never had a problem that a hood become loose or anything like that and a hood is heavier than a filter.

Just dreaming here though.

Well Hoya has Pentax and have Tokina as a good friend.
B+W is part of Schneider and they also have Pentacon/Practica.
As you know Samsung lenses are sold under the Schneider name so they at least have some connections with each other.
They could make an adapter for their lenses so that you can still use threaded filters so it wouldn't hurt the lens sale.
I can surely see that if B+W and Hoya make the jump to make a bayonet filter that soon others will follow.

Too bad it didn't catch on John.
Strange actually...
In the time when B&W film was popular (sixties?) some people surely would have thought that a thread takes quite a lot of time and fiddling around when switching colour filters, or white balance filters for colour film.

Wow they didn't really thought that one out

First two aren't the problem it's the last one that's the deal breaker.

Just look at the way most lens hoods are attached, the functional bit is just as high as the filter thread inside, it's only slightly thicker though but I'm happy to trade in 2mm to make it easier and faster to remove the filter.
And bayonets aren't so keen to get stuck like thread can do and also sand or other dirt would be less of a problem.

For compatibility, I can't see why B+W or Hoya (maybe together) can design one and submit it to make it into an ISO standard.
Some lenses mostly in the range of normal focal length and above might be able to use adapters?
For wide angle lenses though it might be a problem.

Still it needs to be adopted by lens makers and that might be a problem...
Still lens mount also went from thread (m42) to bayonet (k-mount) so it can be done.

That they didn't tell
Does it even happen when using APS-C sensor?

It's quite a pain to remove or attach a filter to your lens because they are using threads, I often wonder if it would not be easier if they use a bayonet instead.
It would probably never happen because almost every one use the same method to attach a filter and the products available for it is enormous but we can always hope right.

Are there maybe other reasons why to use a thread instead of a bayonet?

Thank you Tim, just read though that you can put a 82mm filter in the hood
Looks like a good lens though but still would prefer to have the Pentax 12-24 even if it was just for the name.
Here are some test on photozone.
Sigma 12-24 on Nikon link

Sigma 8-16 on Canon link has a strange wobble in the distortion, that's hard to correct with most software a nice even curve is most of the time easier to correct.