The issue I see with Chademo in the US, is there are not a lot of charge stations available, and almost none of them are where I want to ride my EX. Looking at a Plug Share charging station map, there is one Chademo station in Boise and the next closest station is about 45 freeway miles away. That is way to far to go on my EX, so really of no use. They don't have Chademo stations at MX tracks or in the woods were I ride, so not sure I see the value. No real gain with Chademo capability for my style of riding.
On a technical side, what are you going to do with the heat? There are riders on this forum, I am not one of them, that ride hard enough to have the battery pack go into thermal limiting when they are riding hard. Seems to me you will have the same issue with fast charging so how do you plan on managing the heat generated by fast charging?
Now if you have a reasonably priced, portable, fast charging option, there would probably be numerous forum members wanting something like that. Something you could take into the woods, or at the track, and go from near empty to full in 30 minutes would be useful. You would still have the issue of heat, but being able to move a fast charging station to where we want to ride would be valuable. Probably wouldn't even need to go to Chademo, just a 6-10kw charger for the bike would be useful. That would be a 45-60 min charge from empty and you could do it from a standard 50 Amp circuit in the US.