Meh, if Nintendo wants to carve out their own part of the older demographic and doesn't want to take huge risks with a new IP (game development is expensive nowadays), GTA ports aren't going to help much. They need exclusives and GTA is too violent, it's too much of a leap from Mario and co. A better route to go would be:
1.) Bring Back 007 - He's always "cool" and he's even parent approved as your mom probably thought he was cute growing up and your dad still wants to be him. He's a good fit with Nintendo, ink a deal with EON for rights to exclusive Bond games (at least on Nintendo platforms). Spend a few bucks and get Daniel Craig (or whoever they hire afterwards) to do TV/billboard ads for you. A little Bond charm instantly makes your product several notches cooler.
2.) Make The Console Zelda games a touch darker. There's no denying it, Ocarina of Time and Twilight Princess each have outsold Wind Waker + Skyward Sword combined. Save the cartoony Zeldas for handhelds, keep Zelda on consoles realistic, the audience has spoken. Never go too dark, but push the series to be a touch darker and more action oriented, keep the great dungeon design and sprinkle in moments of wonder as needed.
3.) Metroid Spin-Off. Samus isn't Master Chief, but maybe surely there are other bad-ass bounty hunters in the galaxy. Make a more action oriented sci-fi epic around other characters. The first game can be called (insert character name here): Metroid Hunter. That way you're sure to get a few Metroid fans the first time out and that's the safety blanket Nintendo likes to have. Samus can go back to Metroid's roots with a new adventure on the 3DS.
4.) Be Patient With Platinum Games. W101 is a flop most likely (kids don't like kids games unless they're established characters I guess, right Puppeteer?). Bayonetta 2 may not set the world on fire either. But be patient with it. Build an audience. Greenlight Bayonetta 3, buy out the franchise fully from Sega.
