It's an exclusive so it should be easy to optimise and have a stable framerate.
Strange logic there. It's being developed for 2 dissimilar hardware platforms.
The fact they are both being peddled by the same company doesn't make optimization easier there.
Obviously, it is preferred if they can get framerate stable, and no reason to think that can't happen...
Again making pessimistic predictions based on early pre-release footage is hardly a proven approach.
For all the people that can't seem to handle that, would you prefer Nintendo not release such footage?
It seems pretty simple, if other games were unstable at this stage, yet were so at end, it's non-issue.