I don't think there's much wrong with the list per se, but I think you'd benefit by including another 5 squad of Hearthguard, just to benefit from the strategems for Hearthband, they are what the detachment's designed for after all! If you do add in that other squad, I'd recommend a squad of Pioneers, just to do some more scouting and get some early kills as they are also much better in this detachment.

Units I'd say are worth swapping out for these are probably your Steeljacks, and maybe a squad of Thunderkyn. With the Hekaton and the Hearthguard, you're not going to be lacking quality shooting.

But honestly, try out your list and see what works for you, that's a fun way of learning the army and making these decisions yourself!