Well, of couse the pulp "lifts" don't end with The Shadow. Batman also dresses like a bat (ala pulp hero The Black Bat), answers a signal flashed from the top of skyscraper (like the Phantom Detective) and accesses his secret cave via a grandfather clock (like Zorro). There was even a "Commissioner Gordon" who starred in his own pulp tales.
Still, no one ever said early comics were created in a vaccuum. Finger himself was the one who put these guys on the track of the Shadow source material by mentioning it in the Steranko book. In a medium as disposable and ephemeral as comics were thought to be in 1939, it'd be a shocker if creators *didn't* steal from other sources.
The issue with Kane isn't that he swiped images (you'd be hard-pressed to find an artist who didn't), but that he looked people straight in the eye for decades and swore up and down he not only invented Batman (all by his lonesome) but that he wrote and drew every story until 1964 or so, which is a kick in the nads to every guy who put his sweat and tears into making the character great.
This article is worth reading for this one line alone:
(By the way, Gibson did know Sir Arthur Conan Doyle; they were introduced by their mutual friend, Houdini.)
How freakin' cool is THAT?