Yes I don't think XRP will do anything to "crush" BTC. It's even more different and has different kind of people willing to invest in it.
But thats also the thing the people who feel threatened by it don't get. I don't really know how much it will really affect BTC, but from how things look now it's worse than before LTC took off.
I agree on gox also, although not short term, since the exactly kind of thinking process makes somebody think we "need" gox to maintain a good price, don't ask me for the rationale on this it's mainly irrational - anything changing the status quo is potential bad news for those guys.
XRP potential to crush bitcoin would be very hard to understand unless you know, for example why the price of gold and silver has been crushed during a period where all the main fiat currencies are increasing their quantity of money through quantitative easing. Its too complex to go into much detail here but essentially, many people who don't hold gold think they do when all they really have is an IOU.
The war between using debt as money and using commodity type monetary assests, things that hold value, has gone on probably for centuries. You cant compare Litecoin with Ripples, Litecoin is real money fixed in quantity, potentially good as a store of value just like bitcoins.
It is the power to create money that allows central banks to steal wealth through inflation, just as XRP quantity can be inflated by the Opencoin controllers, this gives Opencoin the power to steal wealth through inflation. The temptation will be too much to resist. Money power preys on weak willed greed, its only human. Debt is a way to enslave. Ripple is a way to replace bitcoins with debt
XRP is not debt. Once Ripple leaves OpenCoin's control, they will not have the ability to change the number of XRP in the system. They may still own a large portion of the XRP, which will give them significant leverage on the price if they choose to use it, but this is very different from having an unlimited ability to print money. For example, you know at any moment what fraction of the XRP you control, and that fraction can never be diluted without your permission.