I think it might be useful to have a new cmavo, {vau'u}, which is in its own selma'o. It would act as a "super famyma'o / super vau"; acting as any number of {vau}s needed to close off a sentence.
Why? Attitudinals, mostly; it'd allow adding attitudinals as an afterthought, attaching it to the entire sentence rather than the last thing in it. {vau} is sufficient for simple sentences (e.g. {do sidju mi vau ui}), but more complex sentences with subclauses at the end may require several {vau}, which just feels wrong. For example
Instead of: {do sidju mi lo nu mi zenba lo ni ricfu vau vau vau ui}
You can have: {do sidju mi lo nu mi zenba lo ni ricfu vau'u ui}