Totally agree with you - seems to be nothing special, on par with current solutions.  Sometimes works, sometimes has tons of artifacts.  I respect them for baring it and not just showing ideal footage.

Twixtor, Kronos, etc are all pretty old in the tooth now to be honest.  Many studios have their own in-house optical flow systems that produce much much better results.  Denser vector data sets.  Better algorithms and edge handling, far less "fraying" for lack of a better word.  Ghosting.

This tech really needs a revisit and more "pro" offerings since many of us have enough computer horsepower at our disposal to go for the better results.  And it's not just for retiming - there are lots of other tools and use cases that can use optical flow for tracking/paint/roto or to accelerate certain processes.  There is a lot of damage to be done here, and Foundry doing the Smart Vector tools over in Nuke are really just the tip of the iceberg.  They could be smarter.  har har.

GPU acceleration is great, and you definitely notice when you're on a machine that doesn't have a video card up to par to use the GPU acceleration on, say Kronos for example.  So it should definitely be on Nvidia's radar.   But whoever goes for the gold and produces the eventual system that will produce the level of results I'm after will understand that this is something that has to be distributed to a *real* CPU render farm at 1 frame per node, and cooked at length.  Long render times, comparing many many more frames than the current systems are using.  Want!