Shields balancing
Shields are illogically OP.
Can you imagine a character, who is not even a warrior, walking around with a tower shield in his hand without even unequipping it? You know, it's not only heavy, it's the same size as human. How can you move with it without penalties at all?
Everything has penalties. Double-wielding is severely punished (i.e. by to-hit penalties and, worse than it, increased energy cost), but fighting with a dagger from a giant tower shield (and running with it, blocking enemy attacks while moving - can you even imagine running and turning that giant list of metal around you to deflect attacks?) seems normal.
I have two suggestions.
First, penalties for double-wielding should be not that heavy. You are already losing a shield bonuses.
Second, shields can be nerfed in one of the ways:
1. Removing DV bonus given by weapon if you are using a shield. Why? Because it's impossible to block with both your weapon and your shield at the same time. TES shows a good example of how this should work.
2. Make equipped shields give penalties on movement energy cost depending on their type. You can either block attacks and move slower, as you have to pay attention to your shield, or put your shield on your back and run more or less normally, but certainly without the ability to block attacks.