In addition to sensor, there is many things that make a great camera, or not just a camera but a video making tool.
I am currently testing Sigma 18-35 and 50-100 1.8 Art lenses on BMMCC with 0.58 SpeedBooster. Very sharp f1.1 lenses even wide open.
The Micro camera expansion port provides control for the camera and lens and that feature is great, but it could be much better. It is not just camera, it is also SpeedBooster and Lens, they all need to work well together.
The taditional way is to have an expensive manual control lens with gears, to attach expensive follow focus, zoom and Iris systems. The above mentioned 1.8 Art lenses are 1/4 of the price of the cinematic T2.0 version of the same lens... and then you need to add the follow focus systems...
Why is that. modern lenses have good and smooth operating focus and iris motors. It is just the control that is not that great.
For good lens control, the Camera, the SpeedBooster and the Lens need to support that. Unfortunately that is not quite the case today.
The 50-100 1.8 provides smooth iris control, it still has the steps, but it moves smoothly in between the steps and often this provides a good result. The 18-35 1.8 does not have this. Both of them provide usable, but stepping focus control, not great. Some native MFT lenses provide very good focus control.
So why does this not work, why do we not have excelent lenses like the above mentioned with good electrical control. There is no technical reason for that and it would not reguire any additional HW, just SW.
There is the Canon EF protocols that are not available for Camera, Lens and SpeedBooster manufactures and these manufacturess do not co-operate. Sure, Sigman could make their own protocol that would provide perfect lens control and the same lens could have also the EF protocols. There is no technological reasons not to and they could make this protocol available for SpeedBooster and Camera manufactures and together they could make perfectly working lens control without any expensive, big and bulky follow focus gear. But I gues Sigma wants to sell the same lenses as 4X price for cinema use...
Not many camera manufactures provide any documented interfaces, some provide LANC, but it is really something that should already go a way, it is very limited control it provides.
BMD provides the Expansion port on Micro cameras, but why not on other cameras? BMD provideds Arduino SDI shield and it really provides good control for BMMSC and probaly some other BMD cameras I have not tested, but why do they not provide the same level of control on Expansion port. Again, there is no technological reason for this.
So when thinking the above lenses, the f1.8 Art versions together cost less than 2000 euros the 2.0T version arounf 8000 euros + folow focus system, same lens, different housing and control, but the f1.8 Art lenses have already very good housing.
Would it not be great to have a camera that would provide smooth control with the f1.8 Art version of the lenses

Ps. all the above mentioned gear, lens, camera, SpeedBooster is FW upgradable, so if they wanted, they probaly could make it work even with the existing gear.