it hasn't been possible to take short positions previously
True, but if they knock it much below 400usd they will break their new toy, people might buy Alts or silver. Hence, BTC 400-600 for quite some time into the future. Pump and dump coin? Although people could just hold and not sell, buy and not sell, but they would have to stop falling for every press release and rumor first. Perhaps work on adding new ideas to Bitcoin could help make it more mainstream. (I like "mBTC" for wallets and such to help with mass adoption)
As for end game, if it is just to be manipulated to death: I have a lot of DRK and in some BTC store of value alternatives like BC, and the network advantage of Myriadcoin is fascinating. Not selling into fiat no matter what, personally.