I like the idea of combining weapons. I would like to add on to that. Maybe a way to create your own weapon, you can use any perk you've previously mastered on a different weapon. I just don't have an idea for specifics on how to do this.
As for PvP armor, I don't really get your point. I don't play a lot of PvP. I was under the impression that all stats for armor and weapons where equal regardless of level. I could be wrong though. I believe bonuses from class, weapons, and armor still apply, but that's it.
If you are just referring to style; I think it should be like DCUO. If you equip a piece you get that style and are able to change it in your character menu.
If you are talking bonuses such as strength, intelligence, ect; each PvP vender sells a different combination of these, pick the one that best suits your play style. Example: 1 vender sells strength and discipline, 1 sells intelligence and strength, 1 sells discipline and intelligence. I don't know which is which.
I wouldn't say any (In my opinion, any raid, exotic, or anything of the sort can't be modified) perk. As for how, others have discussed this with me, and we got that you would go to the armorer (the useless guy in the tower who sells shitty guns? yea him.), have him take apart the gun in question for X amount (I'd say more depending on how rare the item is, as in it's rarity level), and then it gives you either one part of it of your choosing, some of your choosing, or all of the parts, and then, you could go in and apply the parts to another gun or armor (I'd say there be a limit, to it, and that part is thrown away), possibly requiring materials, like a high end upgrade.
As for the PVP, it's a problem of things like the Iron Banner (which many wants to be a permanent thing, including me) where it's not normalized. If you can't hit 30, you won't be at the top of your game, and you're going to be -blam!-ed.
Explain (I never really played DCUO for more than a week).
Faction gear won't get you to 30.
In DCUO whenever you picked up a new piece of armor, the skin of that armor would be added to your inventory as a Style. Even if you got rid of that piece later, the Style would remain in your inventory. This allowed you to keep a certain look that you liked for a character, but still allowed you to change the stats if you found a better piece of equipment later. The number of Styles was pretty impressive, and you could change color schemes at will using several sliders.