I know you're gonna reject me. I know you're gonna not read this (probably at all) and just go straight to the reply with "Dual Wielding has been discussed many times, each time shot down because it seemed broken or it didn't work or blah blah blah." Just hear me out.
Just Wait!

Alright, you all know how Dual Wielding was suggested or at least brought up several times in the past, each time shot down? Well, they were all explaining how you'd fight with each weapon, ie. slash sword, slash other sword; shoot both guns at once; have bomb with both effects be dropped.

Well, I was thinking of a way this could be implemented. As I was thinking about the swords, I was taking ideas from other games where a character had two swords at once. When I got to Sectonia from Triple Deluxe (c'mon, that's not even a spoiler now, it's been almost half a year since it's Japan release. Most of you guys should have at least beat the game or finished watching a playthrough of it by now), I remembered her Rapier attacks were either her three attack combo (swing one, swing other, then stab with both) or multi jabs followed by a dual slash. When I implemented that into my idea, I thought 'Wait. Why does Dual Wielding have to be a whole new Gameplay style?'

Aesthetic Dual Wielding
And thus, I thought 'Maybe Dual Wielding could just be an aesthetic change rather than a gameplay change.' So now here we are. Rather than having it as a new form of gameplay, we can have it just for looks. This, of course, won't be done for bombs because dual bombs just for looks seem silly. It can be shown in one of three ways:
*As a choice that can be turned on and off at will, affecting all swords and guns in your arsenal,
*As a Knight Modifier that affects all weapons (except bombs of course), or
*As a special item that you can add to a weapon of your choice that only affects said weapon, that you can have multiple of at once on different weapons, but is destroyed if removed (like an accessory).

How would it look?
Basically, your knight is now holding two of the same weapon. That means you can't dual wield two different weapons or weapon classes, so if you choose to add that item to your Final Flourish or Valiance, you can only be seen with two Flourishes or two Valiances rather than a Valiance and a Nova Driver or something.

Gameplay Appearance
"Whoa! Gameplay?! You said we weren't haveing a difference in gameplay, Sono! You Lied To Us!"

Just calm down and hear me out. Like I said, there won't be any differences. BUT! I never said it won't look like there's a difference. This would have two ways of being done:
*Nothing changes. Nothing, except for the fact that you now have a second weapon in your other hand. Other than that, nothing. Or
*Your Knight fights regularly, but now they alternate between each sword or gun. For example, the Flourish line weapons would be just like Sectonia's first Rapier attack, with the dual stab justifying the extra damage dealt on the third strike. And the Antigua Charge would be alternating between guns before firing both off together, creating the awfully metallic Hawk or Eagle or whatever it is.

Conclusion
... I don't really have much of a conclusion to say.

Probably should have thought this last part out a bit more.