One has to wonder about the design decisions that led us to Unified Ammo and no reloading.
Warren: "Okay so in DX1, we've got ~40 different weapons and ~17 types of ammunition."
Harvey: "We should try and simplify things for DX2. The complicated interface is killing the console market."
Warren: "Okay, how about you have Unified Ammo, and each time you reload a weapon, you synthesize new ammo for that gun? Need more darts? Make 'em when you reload."
Harvey: "I think that will slow things down, gameplay-wise. Just have one ammo type and no reloading."
Warren: "So you could blow through one hundred and seventeen rounds of ammo using the sniper rifle? Yeah, that makes sense."
Harvey: "I'm sure everyone will love it."
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And just as an aside, I already played a game this year with unified ammo and a circular UI. It was called TRON 2.0. Every weapon used energy, and the upgrades menu used drag and drop. It was a little unusual, but it became second nature after a while.