Holmgang useless?

[Ferth]

Nope. You're screwed like hell.

At the start of 2.1 there was a bug where holmgang wasn't preventing knock backs from things like landslide, but it has since been fixed. I've used holmgang while tanking titan's gaolers to prevent the knock back. It's by no means ideal since the 6 second window is on the short side and the fact that you can't move while it's on means you can effectively lock yourself in place so you can't avoid the slides if you use it too early, but it can be done.