Larger parties would make combat go faster (though maybe not the Encounter) by virtue of having more actions. it would make combat less tedious too, by not needing to wait through the enemy as much before getting a turn and to get to do something, you get to participate more. And with more actions/characters you can kill enemies quicker if needed, which does speed things up. Even if there are ultimately more enemies.
At the least it would make combat more engaging by having more to do rather than wait for the AI a lot.
