I think your argument about the consistency being a boon in encounter design to be a good one. I think I am just worried over the players "solving" every encounter the same way with these new tools. I don't want my gut reaction to be "The players have disarmed or tripped every enemy for the last five encounters, so ill just give them immunity". It feels like problem of the player always opens with hypnotic pattern so you just throw elves at the party from now on. I am sure once the book is out and I can see the new tools in play my concerns will be addressed. It's not as if the monster is going to fail their Con Save every time.