1.It is new in pokemon BW. I don´t now why they changed that but i like that they did that :)
2.If the pokemon in the egg hatches fast so did it change fast so you di´d not see when it change.
3.It´s new in pokemon BW. It´s called ``a critical catch´´. It´s like a critical hit but is for catching pokemon and not kill them :)
Hope this helps :)