I support your first idea, but I don't see the second ever happening. Mainly because that would probably take a full DLC to do in order to get all the coding in, but there is other reasons I can think of. They aren't going to let the player do that with magic as a handwave. The devs stated that they didn't want colors like green and blue for hair because it was too fantastical. <insert your own eyeroll or facepalm gif here>
So a permanent illusion cast on a weapon or armor to change the appearance probably wouldn't fly with the devs. It's not a bad idea though. 
If it's okay, I'd like to throw in a tinting option for the Skyhold clothing. If the devs just talk about the dirt effect (where your clothes and armor get gradually more dusty the longer you're outdoors,) and give the player more options for tinting the causal clothes, I think a lot of folks would enjoy that. I'm on PC, so I can mod that stuff, but I'd like it available for everyone. I'll take some nice darker pants that clear up after a minute or two indoors from dirt at Skyhold versus clothing literally the color of the dirt. That's probably why they went with that shade of brown. It matches the "dirt effect" that they put into the game. That I never saw anyone ask for, but oh well. Probably some quirk left over in DICE from the BF games that I don't know nor care about.