A lot of D-I ice hockey is made up of D-II play-ups. What a D-I/II NCC would allow is the formation of D-II leagues that would cut costs and not have, for example, a Lake State trying to compete with BCS Notre Dame. I foresee the day where D-I college hockey will look a like D-I basketball -- power conferences, mid majors, and the rest. Wherever you are in the landscape, you can find a conference that fits your budget.
It's 7 years to cycle through D-II on your way to D-I. If you're just going from D-III to D-II, you have an X period to ensure compliance, but after year 2, you should be good to go for the championships.
If Clarkson University of Liberal Arts (to take a fictional school) wanted to reclassify from D-III to D-II, they really have to make sure it fits the mission of the entire athletic department and the school, not just one athletic team. So, do I really see anybody reclassifying up? No. The NCAA is putting enough roadblocks in place to make sure a college stays in its place.