Almost nobody does real 'Beowulf' style clusters anymore, if you use a very precise definition, but in the broader sense this would be a compute cluster. I haven't studied the details of the proposal, but I'm not sure why this would ne revolutionary. Using a cluster for rendering video is pretty common. Burn clusters are used with Autodesk Smoke. Smoke used to be quite obscure but now that it exists on Mac it is seeing pretty wide use. From what I understand, Vegas has network rendering as well. Outside of strict 'editing' and into video comp and color, tons of people use things like Nuke and After Effects on a farm and Baselight uses a cluster. So, the idea isn't really revolutionary. It all boils down to whether or not the implementation is good or not, how it gets used, and wether or not it actually makes my life better.
Distributed processing for video editing is quite tricky. Unless you are doing a lot of fancy effects (which tends to happen in something like Smoke, but as far as I know Openshot has less in the way of professional finishing effects. Some of this would include cheesy stuff like lens flares. Most o it would be stuff like tracked stabilisation and degraining which can be quite slow) actually coming up with a video frame isn't that CPU intensive. When doing ordinary cuts only editing, you just have to seek to the frame in a video file, and decide the frame. For a proper editing format like ProRes, this is about as CPU intensive as decoding a JPEG. For interactive editing, that's pretty much it. Schlepping video frames across the network for that is a huge waste. If the remote system doesn't have the right codec installed, you are sunk. As your timeline gets more CPU intensive, you get more of a payoff for having Extra CPUs to throw at the problem over a relatively high latency and low bandwidth link. Figuring out exactly what to farm out and when is a nontrivial task and it won't be possible to come up with a system that works well for all possible use cases.
Anyhow, I wish them luck. Hopefully they come up with a feature set that matches their users needs. I may have to check out a current version. Last time I played with it, OpenShot wasn't really my cup of tea, but it is always good to see somebody getting support from the community to scratch an itch.