He is referencing something that I said a while back. It is indeed slated for replacement. That doesn’t mean that the stat will vanish completely but it probably won’t be on gear and you probably won’t be able to get anywhere near as much as you can now.
I’m not sure where that post is but the short version is this:
Glancing Blow fills a very specific and important role in gear as we can’t remove it until we have a good replacement that we are happy with. Gear interdependence is an important tool that we can use to make gearing a big picture event instead of just a direct comparison between two items. PoE and D2 do this very well with resistances. We really like the twist that we have put on resistances in general so we don’t want to change that. (The following number are just examples, don’t worry about them being impossible or silly). Say you have 10% GB on your boots and you find some unique boots that have a very important effect which you need but the boots don’t have an GB on them. You swap out the boots but now you’re under GB cap so you have to find it elsewhere in your gear. Maybe that means sacrificing a little power in another category to do. Suddenly it’s this balancing act where you have to find the right combination to progress further.
Typically, this effect is achieved with a defensive stat. We are still testing out replacements for it and will be probably more vocal about what that replacement is when it’s a little more finalized.
Guess that wasn’t really the short version.