I don't know if this is possible, but it may be helpful to have a setting that where you would not enter the explicit lengths of the control arms instead the program only uses your uprights and frame dimensions, and would therefore tell you what control arm lengths you need. It is somewhat frustrating if you're designing from scratch and you only know your track measurements,etc.
I agree, but Wishbone is what it is. The math is good but the input can be tough to get together. The Wishbone Input Generator was developed as a front-end to Wishbone to do the kind of thing you suggest. It is specifically for Wilwood Mustang II spindles and a Car9 frame type, but the frame type could be creatively adapted for other configurations. viewtopic.php?f=5&t=13442&p=138964&hilit=wishbone+input+generator#p138964
There are also other suspension design programs that you may find helpful.