Not trying to attack you with this post but. Working as intended.
This is why you need to be aware of your surroundings as you proceed through the level, never just drop down somewhere, always be prepared for something to spawn and always kite up along walls.
If you get flung off because you were standing with your back towards an open space? Bad positioning.
If you get stuck at a wall and get hit in the face through your block? Bad positioning.
If you get surrounded? Bad positioning. The game tips even warn you for it. ‘‘Don’t get surrounded.’’ It’s a core game-element. Fool the Enemies/AI with your movement, boss-dance and keep account for the random elements.
A lot of situations, in hindsight, are often easily avoidable, getting stuck with a boss at the first grim on that map for example - don’t just rush down straight to the grim, have some people head into the building or have 2 people go from the top and two below if you’re uncertain.
You’ll usually either want to grab the grim and run out of that area ASAP or leave the grim and deal with spawns before getting greedy and trying to grab the grim and then deal with spawns.’
Sometimes it’s better to go down at the wall than to be flung off, since it buys your allies some time as well. Don’t be afraid to use triage-logics in this game, a downed ally can take a few hits, use that to your advantage and don’t always outright revive them for example.
And this is not an MMO and not a holy-trinity (tank/dps/healer) game, you do not tank in this game by taking hits, you tank by staggering/killing/avoiding and keeping mobs stationary. Blocking will more often than not stagger something but the act of blocking itself doesn’t make you a tank or invulnerable and I praise Fatshark for keeping some elements of danger and finesse in the game.
If anything I think your point about a lot of specials spawning during the boss is a good one, but the horde has been a major part of any boss since VT1 and is a core-element of a bossfight - this is why you play as a team and aren’t facing it alone, more often than not you’ll want at least 1 if not 2 people dealing with the horde while the person with aggro distracts the boss till it’s safe to kill it. Unless you can down it before the boss comes.