This is an old post, but I believe you’re asking can you have over 100% chance to block and the answer is no. Your chance to block and recovery max out at 100%, that’s when you block 100% of the time. However, let me be the first to say you do not block everything. As I think you’re working on a shield based character. I and probably many others when looking for grim dawn shield builds end up at this post, it’s like the #1 hit for it I’ll add my experience here with others about shield builds.
My character is a Warlord, I play Ultimate, level 100, campaigns done, has 100% shield block and Recovery 100% of the time. The shield blocks 6944 damage per block, my armor is 4155 with 100% absorption, 7% physical resistance (to 13% with devotion triggered), DA is 2500 (yes is low but with a retaliation build, want DA so you get hit but not crit), around 200 flat damage absorption, with 876 natural hp/regen that in battle boosts to around 1500). Here’s the build Warlord, Level 100 (GD 1.1.9.5) - Grim Dawn Build Calculator be aware you need a 9% shield block shield (which I have) which brings it to 100% grimtools is using a 7%. Also, there is no 10% shield block Perdition shield unlike grimtools says.
An armor/shield build with focus on 100% shield recovery/chance is a very strong build, but there are a lot of things that armor/shield doesn’t seem to do anything against. 1.) Anything that seems to come from the sky like lightning, meteors, snowflakes go right to my hp bar. 2.) Ground effects, standing/walking in acid, lava, aether. 3.) Whirlwinds, such as the sand, fire, aether spinning tornados/whirlwinds that move around and can’t be killed. I’m still learning what other things hurt me.
If I could rate the character, I would say 3 out of 4. Bosses like The Messenger, Kymon, you’ll hardly notice any damage face tanking them, occasionally taking no damage it depends if any meteors or lava from the floor hits you. Nemesis, Koorvaak are different, I put Menhir’s will to max and tried to face tank Koorvaak with no retreating/kiting and when I was near killing him he did end up killing me first. So, a crazy armor with 100% shield/recovery 100% of the time can’t face tank Nemesis/Koorvaak. But, it’s a lot better than most, but I have seen some that are better. This the 2nd version of this char, I’m working on a 3rd. My goal IS to face tank Koorvaak and I think this char can… that’s not using pots except the basic healing and mana when necessary. I’m pretty sure if I used pots prior to Koorvaak I’d be able to facetank but pots just aren’t my thing I fight him without any potions up.