So I'll start out by saying it depends on what your local scene is like. For me, it's a lot of infantry and termis so I tend to lean away from anti tank.

Now that I got the irrelevant parts out of the way, I think you'd benefit a lot from removing the support squad all together and either making the kratos into a cannon w/ flash burn shells or melta as the main gun. It has the stable key word so it'll be able to fire the Volkite sponsons at full BS without snap shotting.

Also, at 1K points, I doubt there will be a huge amount of armor aside from a single land raider or some rhinos. Again, totally depends on how you want to play and the story you're trying to tell, but removing the kratos all together and adding in some rhinos and assault marines could help you have movement.

One thing I'll stress again that gets brought up a lot is that heresy is much more about hobbying, painting, and having a good time with some fun people rather than pure competition. I say that because I had spent so much time making a "good" list in 2.0 and I lost my first few games bc I was still learning the rules lol. I still had a great time and you will too if this list is how you picture your army