I think Nintendo wouldn't choose to use haptic feedback if they hadn't tested it extensively and concluded it was viable for gaming. And I think Nintendo, as the designers of a dedicated gaming device, are much more likely than apple to consider and take into account the effects a haptic feedback device they're working on would have on playing games.
Saying it's not viable as it exists on Apple devices right now is irrelevant, since it's possible Nintendo has created a better version. Hence my answer is wait and see what impressions are like and whether or not it is viable. And even if it isn't preferable on a personal level, if that's what we get and it works well enough to be viable, if inferior, it certainly won't stop me from purchasing the system.