Use ActionParameter gem to handle your parameters.
Checkout this article with a comparison of the current patterns used to work with Strong Parameters.
I think it's better to handle parameters in form class. What do you think?
What exactly would be a form class? If you mean something like Reform gem, you'll be coupling you parameters logic in a form class, and the form would be knowing too much and so you'll be breaking the Single Responsability Principle.
What makes the gem better than just using strong parameters the regular way we know it to be. If I'm too lazy to list all the parameters, I use the permit!