Sykar
Arcane
I think you've got that backwards. Doesn't it only decrease guns/throwing/crossbows/melee? So it is good when you have high evasion/dodge.It makes sense for builds which relies on overcoming enemy evasion and dodge so probably yes since SMG builds do roll against enemy evasion.
http://www.underrail.com/wiki/index.php?title=Yell
Mh seems so. Strange I was sure it reduced their evasion/dodge. Whatever.