I don't think it makes it OP, unless that's how you implement it.
If you have a shield, you can guard & bash(maybe make it where dual wield suffers from bash & kick more)
Using a spear/poleaxe you should be able to keep your distance.
Each weapon hand shouldn't be doing as much damage as say a two handed sword. You would have to pull off 2 or 3 successful hits to amount to one attack from a two handed sword.
Also, you could make some other penalties. Like your armor weight would slow you down more, not allowing you to spam. Making you more squishy in battle, as you will not be able to wear heavy armor.
As long as you make some trade offs, I don't see any problems, it's been done in countless games.
Obviously, if it was that easy I would have already done it, tho