Nintendo did try to get into the more 'core' market in the GC days with Geist and Eternal Darkness without success.
It's not their forte as Reggie noted. Mario Paintball would be hugely successful and I don't know why they havn't done that. Super Smash Bros FPS would be even more epic.
Retro could but I'd rather see Nintendo buy up some great FPS studio (not High Voltage... no offense HVS). However at this point no FPS (except Mario FPS) is going to sell gangbusters on Wii. Goldeneye is the best possible bet and it won't have amazing sales either.
Any 'core' FPS from Nintendo should come next gen with comparible graphics to the competition and a full-featured online experience but I don't see Nintendo wading into those bloodied waters. They'll go more blue ocean - Even more for the female market / casual / mature (as in grandma) market.
