Those who argue that there would have not been a rally to begin with (i.e. without leveraging) are kidding themselves.
Here's my stance on the leverage debate.
Momentum is the biggest part of any price movement. You can see this very clearly in the charts... the big trends last for months. If we had not had leverage, we would have had a slower rise (and perhaps even from a lower bottom), but the price would have kept rising instead of running into a brick wall. We definitely could have gotten past $7 without Bitcoinica.