Futures would make the Bitcoin price much easier to manipulate. One major banking institution or other wealthy group could manipulate BTC users in pretty much any way that they want.
Since BTC has less of a clear value than most other stocks and assets, it means that investors could be manipulated to push the price as high (or as low) as they want.
However, I suppose that introduction to a more mainstream and regulated audience could be helpful, as it could theoretically free us from the emotionally unstable investors we have now.
I am afraid I have to agree with that view. Note what is happening on gold markets: they are not trading physical gold, but rather the gold derivative market transacts every day many many multitudes of the value of all physical gold in existence and in effect the banksters are able to withhold the price of gold to artificially low levels.
The same is happening to silver markets, they have been trading derivatives and future contracts until one day Warren Buffet said: ok, I don't want the contract to be rebought, rather, please provide me with physical silver that the contract is for. And he became the owner of majority of silver on the planet
I am writing from memory, but the story goes something like that.
The same MAY happen to bitcoin: if they start trading the derivatives and NOT real bitcoin, they may keep the price to whatever level they want it to be.
This is a real danger I am seeing.