Up until recently if you got surrounded by mobs, and had enough jump skill, you could jump up and over the mobs swarming you, and crowd surf out of the pack. Now if you are surrounded by mobs, your feet get pinned to the floor and you are stuck until A) the mobs around you die or go bother someone else, B) you have max tumble and an ability that lets you tumble through enemies(still really slow to get out), C) you are a druid in winterwolf form and can use snowslide, or D) you Die.
Now couple that with the hilariously unbalanced Shardakai assassins black guards etc that love to invis up to you even when you are wearing a truesight item, surround you, and start swinging their AOE chain attacks that Slow you, lower your concentration, and do WAY TOO MUCH DPS. Why are these mobs given an ability that does more dps to a large area than their single target attacks do? on EH and up three shardarkai means almost instant death for anyone with less than 700hps, and even then... in epic normal there are times when 5 assassins pop out and surround you, if you can't knock em down/stun them instantly your goose is cooked. I have seen the boss shardarkai in the prison hit for 500+ a tick.
Whatever the concept behind the attack was and how we are supposed to deal with it(RUN AWAY) is simply not supported by the game engine(tumble is clunky to use at best, there is not enough time to move, Blocking doesn't stop enough damage)
There needs to be a legitimate counter like with tharak hounds, if they are using it and take damage they get knocked down. Or it fatigues them when they finish and they can't just start up again the moment they catch up to you. at a bare minimum their damage and area of effect should start off small and build over time, granted the moment it does damage it should reset to it's minimum damage and range(you only get one hit with a chain weapon before having to pull it back in and start your swing again)
There is a very big difference between challenging and simply frustrating
This is almost worse than the fire elementals in the SOS chain :| only bring toons with evasion is not a valid counter
TL;DR important part in bold