I don't know why you'd say that Nintendo is afraid of iOS. Or rather, the reasons for them being afraid of mobile platforms is a little different than you are implying. During Iwata's keynote at GDC, he spent a while talking about these platforms and how they are saturating the market with low-quality games that are bogging down the industry as a whole and lessening the value of big budget, well-produced games made by your more traditional gaming companies. He's afraid that the value of content will decrease as the amount of content available increases, which is certainly a valid concern.
If you meant that Nintendo should be afraid of the massive success of iOS, then yeah, I kind of agree. Still, making a sequel to a monumentally successful mobile game on the most successful gaming console at the moment (or its 3D successor, due to launch soon) would hardly be a bad idea. Yeah, lots of "non-gamers" love Angry Birds, but that's the same market that Nintendo had been going after with the DS in the first place (remember Brain Training?).
Railing against the quality of games on the platform is rich, coming from Nintendo, since the Wii is a landing zone for shovelware like never before, and the DS has been just as bad.
I chose to interpret their GDC keynote as an attack from being backed in to a corner. Someone else stole their schtick, and now they are panicking.
If you meant that Nintendo should be afraid of the massive success of iOS, then yeah, I kind of agree. Still, making a sequel to a monumentally successful mobile game on the most successful gaming console at the moment (or its 3D successor, due to launch soon) would hardly be a bad idea. Yeah, lots of "non-gamers" love Angry Birds, but that's the same market that Nintendo had been going after with the DS in the first place (remember Brain Training?).