No, I don't think thats a good idea. Historically when things are removed from the game, they're replaced with nothing. So you're just going to make tanks more dull.
And Invulns in my opinion make tanks more skillful, not easier. Clutch invulns to save runs feel good, using them proactively to save resources feels good.

If you want to make tanks harder, I think you should look at removing "Tank Mastery". Its the lv.1 passive that basically reads "tanks dont have to try in normal content". This used to be a thing you had to toggle on manually between a DPS stance and defense stance, but SE got mad at tanks only ever being in dps stance and forced it onto tanks permanently. Its giving tanks an inherent 20% damage mitigation at all times and a health boost, and its why you can basically get through a majority of content without pressing your mit buttons.

I'd like to go back to tank stance dancing as I thought it was inherently more engaging. But I can't see that happening.