Here's something I'd like to see. Simple weapons should be the simple weapons, ones invented early in time, one's widely used, ones that don't take much skill to use effectively. The spear is one of them.
Then, martial weapon proficiency gives you proficiency in martial weapons, but also boosts your ability with simple weapons. A spear in the hands of a militia member is an effective weapon, but a true warrior knows how to use it better. A simple +1 to hit would make simple weapons very functional in the hands of a warrior.
But, I also would love to see "martial cantrips" for special attacks with different weapons. There's lots of tricks that can be done with weapons, even simple weapons.