[...]and turning into what Last House on the Left could have been.[...]
That is most certainly well observed (as I would expect from you). While the story is actually not quite that similar it is the style that would have served Last House on the Left very well
Maybe Bava had wanted those sequences in and simply ran out of money, so producer Alfredo Leone’s intentions shouldn’t be questioned, but I can’t help feeling the intended finished article wouldn’t have looked so much different to the Rabid Dogs we have now. Losing the opening credits and replacing footage to keep the running time the same is proof even Kidnapped was a compromised production.
The Anchor Bay release Jimmy and I have has a 16min featurette on the Making of both films. Lea Lander (big props to here, she is the one who bought the rights back and then eventually sold them to Alfredo Leone), Lamberto Bava (who filmed the additional scenes and edited the film) and Alfredo Leone (who bought the rights from Lander and released the film) are on hand to discuss the making of the film(s). At some point Leone (and maybe also Bava) points indeed out that he wanted to complete the film the way Mario Bava wanted it. However, if
Rabid Dogs wold have gotten the inserts from Mario Bava as well then I am almost glad he couldn't finish it in 1974... The work print version is so much more powerful, despite only a few bits being different.