(noun) です vs. がある when either is appropriate > ~ > > ~ > > ~ > > ~ These are just two examples. Obviously you can't stick in any noun, but I don't know if these fall into some well defined class either. Anyhow, are there any difference in nuance when formulating yourself one way or the other? I'm also wondering about the negative: > ~ > > ~

The structure affects the difference in the meanings.

> ...
> 'my will is such that ...'
>
> ...
> 'I have a (partial) will such that ... (but I also may have another contradicting will)'

This results in that the former has more determined meaning than the latter (as SomethingJapanese observes).

This difference in meaning also explains what Chocolate and gibbon discuss in the comment. Unlike `` 'will' or `` 'plan' which may or may not be strongly determined, `` 'being ought to' is strongly determined by nature. Therefore, it does not go well with the weaker expression ``, whose implicature that it is "weakly determined" contradicts with the "strongly determined" meaning.