Ick Freemium games.
I'd normally give the developer the benefit of the doubt if there is a compelling reason to have a subscription (reduces hacking and cheating, competition with millions of worldwide players, skilled leaderboards, etc) but if it's just a paywall like a newspaper or magazine, forget it.
Newspapers and Magazines contents are 100% different between subscription periods, so they have a compelling reason to pay the fee. It's free competition is the web in general.
Video falls in between, because services like Netflix offer unlimited content to watch, but may not always have something you want to watch. There are free alternatives (eg youtube) that you would never want to pay for when most of the content is cats in boxes.
But games, have too much investment upfront to basically offer a new game every month, and it's free alternative is also the web, but most of the existing web games are FLASH, and don't work on the iPad. Including some not very compelling flash games, and everything you see on facebook.
So no, I think a subscription-only game probably won't work on the iPad unless it already has a fanbase.