The one aspect of Bungie's armor 2.0 reveal that had many players scratching their heads was the armor-element/weapon-set mod restrictions. As a quick reminder the sets are as follows:
Solar: Fusion Rifles, Auto Rifles, Rocket Launchers, Submachine Guns, Linear Fusion Rifles
Arc: Pulse Rifles, Machine Guns, Shotguns, Swords, Bows
Void: Scout Rifles, Hand Cannons, Sniper Rifles, Sidearms, Grenade Launchers
On the surface it appears you could not, say, equip Void Arms and then attatch Loader mods for both Hand Cannons and Shotguns. To be fair, you can't do that now, but we were promised 2.0 would offer more freedom, not the same old restrictions. Well, apparently Bungie heard you, because on Friday Luke Smith took to twitter to clear things up. And guess what? Cancel the apocalypse - it's not as bad as it seems.
Whether it's true or not, I always assumed there was a hierarchy of efficiency among Loader perks, based on their specificity. Shouldn't a Hand Cannon Loader perk reload my Hand Cannons faster than the a Light Arms Loader perk? The more general the perk, the less efficient it should perform, right? Well Bungie must agree with me, because they're acknowledging that hierarchy with armor 2.0 - then flipping it upside down.
Perks like Light Arms Loader (now renamed Small Arms Loader) will become 'general mods'. General mods, of which there will be 11, have no element affiliation. While the Hand Cannon Loader mod can only be attatched to a piece of Void arms armor, the Small Arms Loader mod can be attached to the general socket of any piece of arms armor. What's more all general Arms Loader mods will increase reload speeds the exact same amount as weapon-specific Loader mods. So to put minds to rest, yes, there are plenty of ways to get your Shotgun Loader + Hand Cannon Loader combo if that's what you desire.
However, there is a downside to general Arms Loader mods. Attaching a Hand Cannon Loader mod, or any weapon-specific Loader mod, to a Void, Arc or Solar piece of armor costs 3 Energy points. But attaching a Small Arms Loader mod, or any generalized Loader mod, to the element-neutral socket of a piece of armor will set you back 4-5 Energy points. If general is now better, general is going to cost more.
I see two major takeaways from this. One, we're starting to get a sense of how important Energy Point budgeting is going to be for creating builds. Even with the (current) maximum of 10 Energy points available per armor piece, you're going to have to make some tough decisions down the road to create your desired load-out.
Second, and this is where I believe things are going to get really interesting, you can now double specialize on a single piece of armor. So if the mods are allowed to stack, and Bungie doesn't interfere too much, we're going to see some unprecedented action performance spikes all over the board. A Small Arms Loader mod combined with a Hand Cannon Loader mod is doubling your Hand Cannon reload speed bonus, and that's before we even add weapon specific perks and stats.
In the end these element-type/weapon-set restrictions are just about Bungie steering players in the direction of specialization. You can still bulldoze through these restrictions if you want to, it's just going to be an extravagant use of your Energy points. I guess if having a ridiculously fast shotgun reload speed makes you extra deadly, it's not so extravagant. At least we get to decide.