Connotation of "to expatiate"

Solution 1:

I looked up the word on Wordnik, which, in addition to showing several different meanings of the word, shows a list of sample usages along the right-hand side of the webpage. (The website starts with 10, but you can view even more with the click of a mouse.)

Neither the plethora of definitions on the left nor the example usages down the right seem to indicate an always-negative connotation to the word. While some seem to suggest that the expatiated diatribe would be unwelcome (please, spare me!), not all of them do.

It seems like a good choice of words when you want to express a long rambling, but doesn't seem to always connote "disapproving."