I dunno. I guess "sadness" is appropriate. I'd be hard pressed to find a gamer who didn't have at least a few good memories with Nintendo systems. And also at least one bad one about their dick friend who sucked people up as Kirby and spit them off at the bottom of the stage. Lookin' at you, Alex...
Of course, Nintendo's not perfect. There are a few business practices of Nintendo's I completely abhor: region-locking (especially annoying, since I'm Canadian and it's the N.A. versions that get censored because of U.S. laws and cultural restrictions that don't apply to me), the restriction of Let's Play content, their decreasing level of originality (though nowhere near as unoriginal as some other sects of the market) and their stubborn fixation with innovating where it's not usually needed and halting progress where it needs to be made, but at the end of the day, I feel as though I can confidently say that Nintendo puts a certain amount of soul into their games. Like Jim said, games like Pokemon and Kirby are made with nothing but love for the industry and gamers. There is no unwarranted money-grubbery happening when a Zelda game is released, because they are releasing a quality product that deserves your hard-earned cash. Despite the staleness present in quite a few of their series, they're done damn well. For example, Pokemon X and Y, at least in terms of mechanical improvement, is one of the series' best to date.
Unfortunately, aside from childhood sentiment, I can't really see a reason why going third party would be terribly bad for me. I'm more of a PC guy nowadays, (at least until Smash Bros. comes out

) and if I can hook up a controller and play Super Mario 3D World, that'd be pretty sweet. Of course, that means Nintendo gets sucked into the crappier business practices that I feel it's managed to avoid: graphics over gameplay or story, shoehorning unnecessary and expensive features into their consoles in order to make them "ONE-STOP-ENTERTAINMENT-THINGIES" while still having at least SOME innovation (the gamepad is gimmicky, but unique enough to justify its existence), homogenization of the market (FPS seems to be the one game Nintendo doesn't have an active series for), and whatever almost everything Microsoft or EA does. Nintendo makes games damned well, but I'd rather they keep making games on their own terms, even if it means needing to deal with their considerable stubbornness.