Michael, I start a new post so that anyone can add some useful ideas.

For sweep
Adjust using sliders the "pointy" effect. Need 2 sliders, one for each point, showing the persentage of the length from the end of the curve to the middle of the curve that the profile used will get smaller until it becomes a point. (Not well writen but I guess you can understand)
Have this as an option, your method will be very useful too. I just want to have the option to have a length with full dims of the profile, not just a cross section.

For loft.
So far, loft is what other apps (like 3dsmax) call blend.In Moi, blending works only between edge curves on solids, I can't see why. I would prefer lofting to be a series of closed curves and a path curve where I can construct a final solid using all of them as MAX does. it would be very useful for things that change dimensions or shape, smoothly from one shape to another along a path.I know that this means more parameters and calculation but if you can control them in real time, it would be a powerful command.
What we have to do with MOI so far, as I can understand, is to use many times lofting and blending but it is not easy and we have not much control.

I would like to hear everyones opinion on this.
Thank you