Do you think altcoins can survive without bitcoin leading the way ?
yes. many of the will survive but the top altcoins, at least the top 10, will die with bitcoin and get dumped even harder if bitcoin goes down.
will the bitcoiners that lose faith go into altcoins or will they just cash out and take profits ?
bitcoiners don't really have much faith in altcoins if you ask me. they all are interested in bitcoin that is why they invest in altcoins, they want to make profit on their bitcoins!
I personally see this altcoin growth going hand in hand with the growth of bitcoin
even though some of the altcoins already offer some exciting new possibilities
almost all of them have interesting possibilities but also almost all of them add more flaws than they solve any issues. you can see ETH for example. it has 13 second blocks but it still can not handle transactions when there is a growth like cryptokitties caused! and that is just a start.