If you're going a speeds significantly above what most cyclists are doing you should be bound by more regulations than cyclists and you probably should stick to the roads and not be allowed to use bike paths.
We already have large speed differences on (bidirectional!) shared paths and it works out just fine. We have kids and elderly walking at 5 kph, same kids and elderly cycling at 15 kph, and more fit adult cyclists going anywhere between that and >30 kph. Other people stand still. Dogs can be problematic but overall I think it really does work just fine, and I don't think anybody needs to fear for their life. We can adjust our speed.
If anything, forcing cyclists on the roads results in even larger differences in speed. But also mass, and awareness.