How much Dev work would it be..

[Vidu]

What excatly would be the benefit of that?

Offhands will still exist for crafters and gatherers, so its not like we would gain anything there.

Before we ask how much ressources it would need, we should ask if its worth any ressources at all - and as a paladin main I dont see why it would be?
Sword and Shield are dropping together, they are upgraded together, they ultimatly cost the amount of tokens or ressources when crafted compared to other classes mainhands.
Having them seperate allows me to mix them like I see fit (if the sword of a set has nice stats, but the shield doesnt, I can pick a better shield) and even more important: I can easly glamour them.
For ninja daggers and monk fists you dont get the option to have one design in one hand and a different design in the other. But I dont always want to be stuck with the shield matching my sword! (Infact, personally, my shield doesnt show anymore)
And finding a solution around the glamour problem doesnt seem to be worth any dev-time to me - specially not when I dont see any problems with the current system nor any benefit from merging sword and shield into one item.

As long as you dont present good arguments why that would be a good thing, any minute spend on this would be wasted in my opinion.

In regards of it saving them time to make them into one item: Why and how would that save a siginicant amount of time? They'd still need to design and model both sword and shield. Okay, they'd only need to coded stats for one item, but I cant imagine that outweighing any hassle they'd have with the whole glamour-thing.