Honestly base name plates should show who a cast is on without physically targeting the mob. Things like houndmasters hit for 40%+ of your hp. This should and hopefully will be updated, if it already isn’t being.
With that said I’ve done my most recent dungeons without addons turned on. Ranging from some 10s a 12/13 and a 15 Dawn. From a tanking perspective if you’ve been tanking the dungeons it doesn’t actually change a ton of things. I mistimed Incarn in an Eco Dome first boss but (this is outside what you asked I know) most things you have enough time to react to (such as Terrifying Slam.)
Blizz said they were going to tune down casts, Eco is to some extent tuned down. But the casts matter more which is an okay trade off I think. The random damage is differnt then Halls (humanoid leap vs houndmaster shot).
But if they are reducing defensives then I have to believe they are simply making this part of the game easier, because people not doing without addons currently, are not going to start doing it without addons later.