Seeing information on Latin, there are many diphtongs, and less consonants, or at least less letters for them.
Nowadays among Romance languages, only Portuguese has a bit complex vowel system (like
bacana sounding like
/ba.ˈkɐ.nɐ/, 2 very different vowels). Italian and Spanish have just plain vowels, and diphtongs simply have
/w/ in them (es:puerta, it:uomo).
I leave French (phonetics of which, as a commenter pointed out, underwent long and complex transformations) and Romanian (which I'm not competent in).
Did Latin have a relatively rich vowel system? Are these languages now having richer consonant assortment?