I am playing with counterattack. For example if something attack you , (in the same attack type)you can attack him in the OL turn too. What about you?

As in a repeatable Guard? I think there's a similar Feat that does this (Riposte or something), maybe just use those? I think being able to attack multiple times during the OLs turn can be a bit unbalancing...

-shnar

This sounds neat from a theme perspective, but I'm with Shnar. the heroes get enough tools already. This house rule would really change the balance of the game.

I find that explanation is not enough for me to have any clear idea how this house rule actually works.

If you're suggesting handing out free attacks to people who get attacked, though, I have to agree that would be a very dramatic change.