I created a similar sort of house rule. Mine is this:
If you evade, you cannot attack on your next CA- with one exception: Small throwing weapons can still be thrown as normal.
One of my players wants to play an assassin who dual wields and throws daggers. I like my house rule because I feel dual wielding gets overshadowed by shields, and this (along with some other house rules I'm thinking of) will give my assassin player some advantages that give dual wielding a unique feel, without eclipsing the other weapon styles.
As for your rule... I'm not sure. I'm not really familiar enough with the system to know if that would break it.