I had the same "fear" at the beginning of my research into bitcoin and when the alternative versions started showing up in 2011 I followed each with fascination.
Long story short: Most of them Failed, unless they offered a "difference" that made them useful in a way that is truly different from the original Bitcoin.
Though not really a simple tweak, or change of the original Bitcoin protocol, I do suggest you look at RIPPLE as one "alternative" that may really perform well in the future! :)
Otherwise, if the new "bytecoin, bitcent, bytedollar, bytecent and bitdollar" ARE EXACTLY the same as bitcoin, and different only in name, well then I believe it will simply be another Bitcoin client(with a different name) that will just work together with current Bitcoin user's official clients and no competition will exist! :)
But if a small change, any change is made to the protocol, and it is truly different from the official Bitcoin protocol, we already know what will happen to Bitcoin: Nothing.
Just plain 'Happy'about the direction the world is taking! Especially if we live to reach LEV [Longevity Escape Velocity]