Max block Gladiator, how important to be at max block 24/7?

Was lucky enought to get relic BoR (15% block chance) and thought that's time to remove some block nodes (Command of Steel branch).
Ascendancy Painforged gives +8% block chance but the buff seems to be pretty short. Am I building character wrong if sitting at 67% block chance but with ascendancy buff it will be maxed 75? The point is how important u think block chance for attacks/spells is 75%
I felt that Painforged is kinda not needed if block chance is 70-72. Seems to be stupid question but playing on HC and would like to hear opinions if I'm heading wrong direction and the point is how much u rely on Painforged triggers?
I'm also wondering how good Tempest Shield overally is since it gives +3 block but doesn't work with ascendancy. The upside the effect is almost permanent at the maps.

And one more question: The surrender or Lioneyes with probably some fancy corruption? Trying to build character good enough to run T15 maps

If you skip painforged then you're skipping versatile combatant. And you'll definitely want that for HC.

I can 78 whenever I want. Never have to. ~63% is fine I think if you're running a good defensive setup with around 7k life.

Yeah. With glad passive and tempest I have 63% (I play hc too). 7k hp but I use sunder so is like a ranged skill. Careful with bleed or any chaos degen. Only thing that almost killed me was heavy degen so have at least 0% chaos resist and atziri potion to be safe (mostly).