Bitcoin is completely uncontrollable. Nobody can stop anyone elses' payment once sent, not even the sender. This would not suit their purpose at all.

Bitcoin is also super-transparent. There'd be no way for them to hide all the money laundering and under-the-table business they do trillions of dollars a year in right now.
Most importantly however, bitcoin simply cannot be counterfeited. They would find bitcoin 100% unsuitable because they would detest the lack of ability to print more of it at will.

Assuming for a moment that there is a group like the NWO or illuminati pulling the strings behind world governments who want a single world currency, it would be fair to say that they would want one that they could retain some sort of control over, right?

I'm sure that they would want a currency they can print on demand and recall whenever they wanted, and of course they'd want to control the networks which it flows over so they can stop anyone's payments whenever they don't want payees to receive funds they don't approve of.