OALD defines verbiage as
[uncountable] (formal, disapproving)
the use of too many words, or of more difficult words than are needed, to express an idea
Wiktionary's verbiage entry notes an alternative definition
(2) (US) The manner in which something is expressed in words
but points out that another way of saying this, like "diction" or "phrasing", may be better if you want to avoid the pejorative connotation of the main definition.
It seems that plenty of people have the same question, wondering if verbiage refers just to words or phrasing:
Nevertheless, we often hear and read such expressions as “too much verbiage,” “excess verbiage,” and “excessive verbiage.” Perhaps the writers of these expressions have the second definition in mind.
As a speaker of American English, I'd agree with Wiktionary that verbiage alone still carries the connotation of lots of words, but to me it doesn't say strongly how you feel about those bunches of words. That would explain why I've never been surprised to see excessive verbiage — the addition of "excessive" makes it more clear that you don't want those extra words.