V1 and V2 are not quite the same as decision and rotate. I guess V1 does equate to decision speed, ie you're no longer going to be able to stop. V2 is the nominated speed to fly once airborne but still with any take-off flap in the event of an engine failure. It's effectively your best climb-angle speed and used until you reach your acceleration altitude.
I guess raising the noisewheel was used on types which were flown off the runway as opposed to being rotated more aggressively and 'hauled' off. Ie, once the nosewheel is up the aircraft will then fly itself off the runway when ready.