This ought to make interesting reading.

[BoyScoutKevin]

Oh, that Avengers. You probably couldn't give that title to a film today without receiving a cease and desist letter from Marvel studios.

It's a good guess about the editing. The film was originally 115 minutes, which now seems to be lost, and was cut back to 89 minutes. Though, the problems began before the editing.
--What was originally on the script did not make it onto the screen.
--The preview audience in Phoenix (Arizona) was composed almost entirely of working class, predominantly Spanish speaking members. Who hated the film.

The good, the bad, and the ugly.

The good
--the cast
--Like a lot of failed films, it produced a book Peter Bart's "The Gross."

the bad
--It was Patrick Macnee's last film, giving his voice to the character Invisible Jones.

the ugly
--Depending upon how you feel about Sir Sean Connery, this film was one the reasons he left acting.
--For the 1st time, John and Emma intentionally kiss.