Light twins not using contra-rotating propellers

Recently, Stefan posted:

Newps schrieb:

I consider the effects of P-factor and torque to be design defects.

Christ your an idiot. Until you change the laws of physics you're
stuck with those 'design defects'.

Be extra careful before calling names! Even when you don't like the
poster.

Of course the effects of the P-factor can be overcome by appropriate
design. The most simple solution would be the possibility to trim all
three axis. As this seems to be a pretty straight forward and cheap
solution, I've never understood why this isn't offered in all
airplaes. Sure would make flying a light single more enjoyably. Yes,
I even agree that this avoidance could be called a design defect.

I think it would be a good idea to distinguish between design defects and
design _trade-offs_ in this kind of discussion. Many GA planes have 3-axis
trim, but, as in other areas, this option comes at a cost. The question
becomes which options a buyer might find more attractive, for example
would you prefer 3-axis trim or better avionics and moving map GPS?

Neil