Play master and see. I would expect you get your rear end handed to you on a nice shiny plate.
Not if you know what you're doing.
If you want to use smithing and not be overpowered then just take the steel and arcane smithing perks, then just improve what you find.
What build are you going to use? I didn't have to much trouble with heavy armor, block, 1h, restoration and conjuration (without smithing). The most defensive way you can play, I don't think that character even died on master, came close though.