"Morphogical syllables" (maybe renamed to something a little less susceptible to confusion) would be fine. My questions would then be what the rules are and why. The norms of language don't constrain morphophonological rules much, so they can be as weird and wacky as necessary. The rule you give below, CVC*, seems pretty straightforward.
Actually, that's not quite true. We do need to identify valid onsets
in order to determine words, but this discussion wasn't really about
onsets.
The question about onsets being whether CGV is a valid onset?
But "morphological onsets" are needed too, aren't they. E.g. /patrAma/ is two words /pa trAma/ whereas /partAma/ is one word, because of the rules for morpho-onsets.
Well, today's morphophonology is yesterday's phonology (e.g. the vowel alternation in _sane--sanity_), so it makes sense diachronically but not synchronically. But for Lojban you don't look for diachronic explanations. (In Lojban too the actual explanation is of course quasi-diachronic, in that the complex constraints on 'clusters' were likely invented before the buffer vowel.)
Without a buffer vowel, it does make sense to limit the amount of
consonant clustering that can occur. If there was a buffer vowel,
the morphophonological syllable could still be onset-nucleus-coda as
now, but with the coda allowed to contain as many consonants as you
wanted. That's not how my dialect of lojban works though.
In what way is it not how your dialect of Lojban works? It would categorize as valid some words that you categorize as invalid? Or would it insert word-boundaries differently? The latter seems more significant an objection than the former.
So anyway, do you advocate abolishing the buffer vowel? An alternative would be to insist that every licit phonological string has both a CV syllabification (with buffer vowels) and a resyllabification without buffer vowels. That alternative strikes me as needlessly complex, but as still preferable to abolishing the buffer vowel.