Altcoins are paired to bitcoins in determining its price hence when bitcoins moves up the other altcoins will follow. Altcoins are dependent but the effects of bitcoins price have a slight effect on them.
That's right. Those who believe that ETH or LTC will do good will have to wait until BTC starts doing good first. The general mood is one thing, but going into extremes, if BTC manages to skyrocket again, everything else will. I've seen worthless altcoins grow during the largest bitcoin bull markets and I've seen they all suffer a much greater fall than BTC when it went through a correction. If you want to put your money into any altcoin, you can as well put it into BTC and the effect will be pretty much the same, at least when it comes to timing.