Most of the altcons will grow only when bitcoin grows. In the end of march there will be tokens burned by several projects. This will definitely impect on the price
Not all of them will only grow when btc grows. Some coins are kind of resistant to market falls or at least does not fall so much. I think when most ICO start delivering their product and tokens/coins can be used to pay for services/goods and people actually start using them - we will see *hopefully) separation from bitcoin. Or at least bonding with it will not be so tight.