pdq,
I would disagree with your feelings that Douglas was a better talk show host. Mike was "nice" but was not as good an interviewer. Merv's delving intuition made for much more interesting & humorous talks. He could sense when there was a good story afoot.

He made one movie & in it sang to the lovely Kathryn Grayson. Can't recall the name.

Arthur Treacher was a delight as his sidekick. His "My Dear Boy" admonishhments would put Merv in his place when he got "fresh." Merv loved it.