Spoiler: Click here to viewI think something must happen to the nuke (to cause the effect of pregnancies, but I can't imagine it'll explode (at least in a conventional way. The Man in Black has already shown that he can affect bombs (he did with Michael on he freighter at least). I just can't see the island going though. What we saw in "The Incident" makes too much sense. Pierre Chang getting his arm trapped (he only has one arm in the later DHARMA Orientation films), and Radzinski surviving (so he can push the button).
As for the 77' storyline being boring. If you mean watching it - I found it entertaining. It was interesting finding out more about DHARMA, and how Sawyer and co. settled into a nice life. Storyline wise, they caused the incident, and are different people after experiencing it. Maybe they're more ready for whatever's in store for them in 07'.