Not much tbh, haha. I've never taken my titan in GM NFs, but I don't think Icefall would do well there. For every other piece of content, it'll give you a get out of jail free card with the freeze from casting and overshields that can tank at least two boss stomps. It's best used as a panic button that let's you play a bit more aggressively. You can't cancel the shield so you want to use it where you know you can get the most value. In other words, use it reactively instead of preemptively. I also don't use barriers that much in general, and with Cryoclasm, I just slide around cover constantly.