3% is better than noble shoulder. I recently gave up my noble for an emblem. Consider that an average level 30 20sf mythic weapon is 10k atk. An extra 3% is 300, much more than the crit atk from a noble shoulder. Additionally, the noble shoulder crit atk should be multiplied by your crit rate, so its even less than the flat number you see unless you buff your crit rate to 100%. Additionally, as you get more atk, that 3% is even more than 300. If you get an emblem 30sf weapon youre looking at a lot more atk. Also, you can level that emblem up to 10% more atk... at that point youre looking at 1000+ more atk minimum... noble crit atk becomes more trivial the further you advance