As for margin requirements, this is temporary, and it's going to be fixed properly soon.
Good. We are still in turbulent waters after the last crash, so it is normal that margin requirements are still high - as long as it is a temporary measure, and not the "new normal".
Maybe you should have a "volatility index" and use the volatility during the last month or two to determine the maximal leverage :-)
The VIX is calculated from options prices. For this, there are several possible choices of volatility, but options is actually the worst one because of the huge spreads on MPEX. I agree with the general idea though.