The longer the melee, the easier the battle. It is the same reason why MTW was incredibly easy, one spear unit can soak a bunch of other units while you flank with the rest.

As for the bonus, I can't say for sure it is gone for infantry. But heavy cavalry is definitely overpowered. I believe the battles are more manageable since the skirmishers are now working.

I have to fight more barbarians to be sure. I've dealt mostly with the greeks after the patch.