I think if Metallica out performs AC/DC in sales then Kiss would be mad not to take advantage of some money over no money to have a 2nd pin. At least Kiss with there costumes adds some creativity to a game like Metallica's artwork over some other possible bands which could be seen as quite bland in appearance.
And agree with CC, Hendrix pin could be a bit funky, given the reggae background, I bet if it paid out in joints it would get the teenagers in 
KISS reject anything that does not make them money. the stern deal is not good enough. The pinball is the ultimate piece of merchandise of the most merchandised band of all time. My generation can afford a NIB KISS pinball.
A Hendrix pin would be an awesome idea, but what of the generation gap ? Back to the 60's - it would be marketed to an older generation. Like the Elvis pinball, it may not be accepted. I would seriously look at a Hendrix pinball, but it would depend on who made it.
Right here and right now - Metallica / Iron Maiden was the logical choice.
All music pins now are marketed to an older generation. IE us, no spring chicken here.
I am sure the kids are stoked there are metallica and acdc etc to buy and play, most of them couldn't care less.
All that matters is if a pin will sell to our demographic.
Hendrix pin done well by someone, anyone would be EPIC and would sell.
