Please explain to me how something like margin trading takes more than a year. In fact, mtgox was so slow that zhoutong went ahead and made Bitcoinica.
Now mtgox wants to reverse the effects of their incompetence by blocking Bitcoinica from timely withdrawals.
Seriously, if I work at Mt. Gox, I wouldn't be able to finish margin trading in a year. Mt. Gox has a very professional trading engine and I don't know how to add margin trading facility effectively.
That's why Bitcoinica is not an exchange and will never be. I initially had the idea of Bitcoinica on September 3, shared with a few friends, and then launched on September 9.