sin/shadow dcds arent great imo since you are extremely susceptible to stunlock globals if you miss the right timing because of the squishiness of the class. if played right, you can mitigate tons of damage obviously.
what bugs me most is the loss of phasewalk. I used to use it in combination with vanish for guaranteed success to heal up in solo ranked etc. now that pw is gone you basically have to force speed out of the engagement and hope nobody charges you or aoe spams while you spam your vanish. more often than not I found myself in stealth but also in combat and have to wait painfully long amounts of time to get outfight and be able to regenerate. it's just annoying to see maras being the better stealth class these days. they can vanish every 45sec opposed to a sin's 75sec (IF specced, else it is 120), pop predation and run across the entire map, up to a distance where you automatically leave combat. while in some occasions they get chased by other maras, it generally feels much more effective than assassin's vanish, creeping across the map desperately trying to get out of combat while your team is just dying.
if sins dont get back PW I would like them to get something like 100% speed boost 10sec after using battlevanish or so, to make up for the more often than not failed attempt to get out of combat reliably. I mean, that is pretty much the classes' theme after all.
alternatively, sins/shadows could be made immune to being put into combat mode for a few seconds after using vanish, as long as they dont use offensive abilities.