If they don't get something out at Photokina to compete with the GH4, I suspect most of the low budget indie crowd will consider Canon dead in the water, and start migrating, unless they've already got too much invested in glass and already have a 5D Mk III.
Low budget indie crowd is generally shooting Alexa.
There's low budget, and there's LOWwww budget. My low budget crowd thinks I'm big budget with a 5DIII setup
What content are you producing and for what client? For low end corporate it's absolutely a viable solution, but do those clients care about 4k vs 1080p or do you and are you looking for the opportunity to sell 4k to your client so you can try it out?
The issue is the GH4 might be great in terms of IQ, but the C100 is the rock steady wedding videographer/event videographer camera with amazing ergonomics and battery life and ease of use. (And the C300 one step above for low end TV/high end corporate.)
Canon can charge more and deliver less because they're targeting "pros" who care more about return on revenue (and have a revenue stream) than hobbyists, who care about image quality but don't have the cashflow to justify the expense. The C100 is a joke spec-wise as is the 5D Mark III for stills. Both are market leaders. They're easy to use and affordable enough, but too expensive for hobbyists to buy (unless they are committed, I guess).