I only do video, and I DON'T want the traditional Camcorder / Video style body. Those are super dated and horrible to use compared to the DSLR form factor which is GREAT.
Think of it this way, would you want to shoot stills with a lunch box style body? NO. Video and photo are no different in how you hold the camera. The DSLR form factor allows you to hand hold a camera nicely. The Lunch Box / Camcorder format requires a rig at all times. SUCKS and is super dated.
That is why the C-300 has a more DSLR form factor, because it's where everything is going.
Let me know when you get good footage from using a DSLR handheld. You need a rig no matter what, especially with a DSLR. Video and photo are both different with how you hold a camera, that is, unless you shoot video with your eye against the LCD or photos using the LCD rather than the viewfinder.
What pros want is features and it's simply not possible to fit all the needed features on a DSLR (they hardly fit on the C300)
From the day the Cinema DSLR was announced I have been saying that the DSLR form factor should be tossed out the window. I'm guessing the DLSR form factor works perfect for you so maybe the 5DMIII would be a good purchase over a C-line camera.
tjc320, the DSLRs are much, much better for handheld shots
Take a look at this video I directed and DP'd recently. About 70% of it was shot purely handheld. NO RIGs. Even when using the 100mm L macro, I still shot it handheld with NO RIGs.http://www.builtbyugene.com/mov_clients/DUEL2_ColorGradeMX_0401a.mov
I shoot a LOT of handheld with no rig (a big part of my aesthetic) and it's MUCH easier on a DSLR. You can view a bunch of it on my url:www.builtbyUgene.com
Of course you can't fit all the features of a traditional video into a smaller body (such as ND filters, but I'd rather use a variable ND), but there are also many, many advantages to having a small body, such as good hand held (very important to me) and the stealth factor.
As for what Pros want, I'm not sure how you define "Pro", but I have been working solely in TV for over 10 years as a Director / Designer / DP and what "Pros" want is as varied as what many hobbiest want. There is no set camera that meets the needs of everyone. But I definitely know what I want; and I don't want to go back to a lunch box body because they're much less user friendly.
I obviously don't want things to go too small (like a point and Shoot), but I feel something like the 5D body is a good size. Not too big and not too small. The Sony FS-100 is a DISASTER in terms of interface. It's too big and has too many buttons. You don't need a button for everything, as Sony seems to think. It's much smarter to just consolidate all those buttons into a few and just design a smart interface for it, kind of like what Apple does with the iPhone.