It seems to me that the proposal as it is does not go far enough.

Would it be more natural to have a "vector of homogeneous elements
tagged with the common type" (something one would maybe call an "array")

and consider the types f32, f64, u*, s* mentioned in the proposal as
elements
of the corresponding vectors to be an extesnion of the Scheme numerical
types?

In fact, Scheme has one such "array" type, namely "string".

Best regards,
Dmitrii