If you're hitting all the time in IA the defender is probably defending wrong.
That said, I do like the multi-dice systems in Armada and IA.
X-Wing could still introduce new dice ... simply introduce a new die in a ship expansion that uses the new die, with upgrade cards that allow the new die to be used on other ships. Then if you have the die, you have the upgrades to use it, and vice versa. So for example:
Black Die: Double hit, crit, four hits, two blanks
Modification: Enhanced Weaponry (2 pts). Replace one red attack die in your dice pool with one black die.