(3) The language must be made slightly less verbose. Looking at Interlingua prose literature, I can see that authors have already voted with their manuscripts that esseva, essera, and esserea are too verbose and too unnatural for optimal modern literary use. The forms era, sera, and serea are superior and look more believable as natural-language forms of the verb "to be" (past tense, future tense, and conditional mood, respectively). The same goes for the imperative, sia. Other similar improvements might be adopted but care should be taken not to deviate too far from what Interlingua is: natural. It should not become artificial. However, as Afrikaans and Indonesian show us, there is no need to conjugate verbs for person; therefore I reject son and somos. Conjugating for person would be fine if the design philosophy of the language required it and if such conjugation occurred for all tenses, but irrationally and randomly drifting towards natural Romance languages by using son instead of es without having any equivalent for the past tense is a recipe for disaster. On the other hand, using widely (and indeed officially) accepted forms like era and sera is necessary in order to streamline the language and make it less "clunky".
To get there, however, it must embrace the future and change.