We can certainly increase bank open position limits, and will do so over time, but it would not be prudent to place all the exchange risk on banks. A better option would be to allow more players to hold open positions without an underlying, with some limits so that we do not get excessive speculation or attempts at manipulation by single traders.
This strikes me as a clear example where requirements and expectations should only evolve through appropriate rulemaking processes, consistent with underlying law, in order to promote a level playing field.