
Alissa G. answered 06/29/19
English & Spanish Language Lover-Grammar Geek-Word Nerd
This is a really interesting (and complex) issue! Although I admit I don't know formal grammar to the extent that you have laid it out, I would say that "want" is the main verb and "to go" is actually a use of the subjunctive mood with "him" being the subject of that verb. I am basing this off my knowledge of the Spanish language, which more clearly lays out the parts of sentence.
In Spanish, this sentence would read, Quiero que él se vaya.
Here is the breakdown of its grammatical structure:
Quiero (I want) que (that) él (he) se vaya (goes).
I know it's a little different since it uses "he" instead of "him" and the relative "that", but I think historically in English it may have been a little different as well. We probably should be saying something like, "I wish (for) him to leave."
These are just my two cents. Like I said, my knowledge of the subject is not as deep, so take it with a grain of salt! Hope it helps, anyway.