Sherlock Holmes - tons of gameplay potential and a solid theme that most people are slightly familiar with but leaves a lot of room for interpretation. A modern Who Dunnit please!

Robin Hood - same as Sherlock Holmes, but I don't think it's quite as interesting or as full of possibilities a Sherlock Holmes could potentially realize. They'd have to have a Daryl's crossbow equivalent right?

Valkyrie - I think the genericness of this allows the most possibility to wow someone. There's no preconceived notion other than it will be something vaguely Norse and full of artwork of sexy, powerful, warrior women from the heavens. Strong art potential and a very unique theme, do not cheap out on the aesthetics! Has huge potential to appeal to women or repel them depending on how it's done. Mandatory to see a Valkyrie pick up and carry a ball off, maybe like the flying monkey and Woz.

Poker Run - so many car games and so many games based around cards/poker, and the concept of a Poker Run isn't well known. Boring theme overall, but there is some gameplay potential I suppose. Doesn't seem super desirable unless there is a killer gameplay hook.

I think Sherlock Holmes is the best, I'd be interested in what they'd do with Valkyrie, I'm a little more ambivalent towards Robin hood, and a meh to Poker Run.

They're applying for trademarks on pinball games. The other manufacturers could still use the themes, but they would have to not infringe on the trademarks granted to American Pinball for "pinball games, pinball machines, pinball-type games, and slot machines".

Ie American Pinball can sell "Sherlock Holmes" but if Stern wanted to do a Sherlock Holmes game, they would have to come up with a different title. American Pinball would have the right to take Stern to court if they think Stern's game infringes on their trademark. There's nothing stopping Stern from using the theme, but they would have to work around American Pinball's trademark (or Stern could take them to court and say that the trademark should be invalidated)

edit: Think back to when DE and Williams were going at in court. Williams trademarked "multiball". That didn't stop DE from having multiball, but they had to call it something other than multiball (triball).