Thanks y'all for some very creative feedback. Felt like attaching a Bonus Action was unnecessary (and unprecedented) but I like to start off underpowered and build from there. Im leaning towards
@dnd4vr and their recommendations but eliminating the +1's, so it would look like this
Versatile Weapon Style
When wielding a weapon with the versatile property using two hands you may also add either the finesse or heavy property to the weapon description. Additionally, when wielded two handed you may use your reaction to increase your AC by 1 until the start of your next turn.
Think we're getting there, what do we think gang??
Thanks in advance!