Yeah they could split it but unless something in the game play mechanics change you would still go full str for more dps. Or you could do as is currently done and mix match str and vit access.

They wouldn't have to change the stats to nerf or buff damage simple modifier or potency changes is all that is needed. If you wanted a tank stat they need to add a mechanic that requires it. Take secret world for example you needed to reach a certain block threshold to not be penetrated wow did it with crushing blows. This way a tank would be required to cap a stat specific to them. Changing there attack power modifier from str to something else is just flavor text.