My Ego was made soley for looks till Wing Bow becomes Ego-able, so I understand the flaw of Ego Masamune.
I prefer dual-wielding due to the fact that I can simply add in FH to the mix for agro handling (expecially in Defeat Fomor Commander II which I run daily).
I'm not saying 2h Ego is bad, but I focus my build around highest maximum damage obtainable alongside with high critical, which 2h Ego just doesn't deliver.
Quote from Archibald;34385:
Someone run the calculations of a level 50 dustin sword (240 max) vs a shadow hunter spike Blue Flashy dyed(cause flashy adds damage) 114 max + level 50 ego glad (175 max i think) for wm.
[Bare hand damage + weapon damage] * skill multiplier
[(Bare hand damage) + (first weapon damage) + (second weapon damage)] * skill multiplier
Let's say you have 100 bare hand damage for the sake of calculation.
DSKS: 340 * 2.5 * 2.5 = 2125
Dual: 389 * 2.5 * 2.5 = 2431.25
So unless you care about that 300 damage difference like me, DSKS still is a good Ego weapon.
Edit:
I never had any problems with multi-agro situations with dual-wielding. Barely any of the monsters are more than 2v1 in Hard level Shadow Missions, and Ciar Advanced doesn't need "heavy" agro handling when you can kill everything in 1 Windmill/Smash.