CPL Vs Linear

[Ptyler22]

Or they could have a polarizer that didn't need rotating at all, I don't know it they could do that by like "overlapping the polarization" if that makes sense, it would be awesome if they could do that. I'd buy one!

 

[Overread20]

Coken (SP) filters and a filter holder would do that job - not attached to the lens at all, but on a filter holder so the lens can rotate all it wants, the filter will remain in the same position.

However as dcclark said sometimes you want a different effect for a different shot so you need that rotating abilty in order to be able to set the polarizer to the right setting

 

[Dwig]

Or they could have a polarizer that didn't need rotating at all...

Not possible at all. The basic nature of the physics that makes polarizers effective mandates that the have an orientation and that that orientation must be set specificly relative to the light that you intend to block.