I am glad that the prices are finally dropping for these models.
Already, the inherent 4K sensor quality (downscaled to 1080p output) is very beautiful, along with the AbelCine profiles that can be added to the C100 MI/MII. Nevertheless, if Canon is going to survive in this market, they cannot have the mentality that they are a competitor with more prestige companies when their C-cameras only have 8-bit capabilities. Yes, the new C300 MII and the upcoming C500 MII have 10,12,14 bit capabilities, but for the price of a new car ($16-30K).
Canon has great ergonomics built into their cine-cameras, as opposed to others who provide "big brick" designs with extra accessories to be attached for a lot more. For a run-and-gun cinematographer who needs versatility to do a wild-life, police, or extreme environment documentary (i.e. war, tight spaces, etc.), then the C-series is great for weight and portability - including the versatility of Dual Pixel EF lenses and clean higher ISOs (among many other great features).
Since so many people are crying foul to Canon ever since Sony has been flooding their tiny DSLRs with video features, it will be interesting to see what video features will be placed in the new 5D and 1D series. Nevertheless, essentially, making the 1D camera into a "new and improved C100"ish" video camera will have fundamental problems IF Canon does not:
1. Improve dynamic range and extend those 14-15 stops into the compressed video footage.
2. Add proper ventilation for heat generation of internal components.
3. Address rolling shutter from an EOS sensor.
4. Provide more than an 8bit signal with an internal 4:2:0 color space.
5. Bit rate of data transfer, even though the cameras are rumored to support C-Fast cards now.
6. Add additional color profiles, etc.
However, it essentially becomes an engineering problem and a marketing strategy issue (for both Nikon and Canon alike).
There is a split in philosophy between photographers in terms of the type of professional body that they want,
but essentially, a full frame 35mm camera with professional features should be optimized primarily for the professional photographer.
The Sony A7s II and alternatives pretend to be professional photography cameras: compared to the dynamic and extensive engineering in the D4s, D810, 5D Mark III, 1Dx of the past, and the new D5 and 1D series to come, when there are many variables that do not match with the small Sony series.
Fundamentally, the C-series camera bodies are designed for video*, whereas a DSLR is not; however, a DSLR should have video improvements, so long as the main features of the DSLR (in terms of photography) are not compromised to satisfy an amateur video market.
*Note: It is important to understand that despite the C-series having the improved cinema camera design over a DSLR, it is very sad that Canon chose to cripple / handicap the internal specs for the sake of marketing! 8bit, reduced color spaces, and not offering inherent 60p as well is not an excuse for the money that they charge!!
Sony provides these features, and many more, in their FS7 and FS5 models for the same price of the C100 MII and C300 MI; however, there are disadvantages as well from Sony - limitation in lenses, color profile look, ISO, footage processing, etc.
Obviously, to find the ideal camera is very difficult with a limited budget. The best philosophy to have is ensuring that the tool that you are using can help you tell the story that you want with the least amount of headaches. In the end, choose the lesser of too evils for what you need to accomplish the project that you have to fulfill.