Bitcoin is still very small - it's market cap is smaller than Apple's, so it's easier for whales to move the price, especially as the trading volume is only about 1/50th of bitcoin's market cap.
However, some of these things will change overtime, if we indeed start seeing real life usage with a great level of adoption but until then, we just have to get used to it. Also, based on what the OP said, I do not see how this inhibits the development or growth of altcoins as a whole lot of alts have grown since their inception and still growing.
Stability should only be expected maybe when bitcoin has gotten extremely huge and by then, it is no longer about investment as an early adopter, but a currency as that is what in the long run, that is what is going to make it hugely adopted and in that stage, nothing much may be expected.
A stable price usually will turn the altcoins more like into a stock market scenario as bitcoin is kind of pegged to them as someone rightly said. This is the main reason why we have seen a lot of altcoins doing well whenever bitcoin is experiencing some consolidation. A huge level of stability in bitcoin is not even something anyone should be expecting at all. This is a decentralized market, there would always be fluctuation and it can only reduce to some certain extent once we get to see real life usage.
Beside the shadow of its stability the instability is also an advantage to those who can not afford Bitcoin. At low price people can easily buy Bitcoins.