Forgot about The War of the Flowers. I really enjoyed that one. It was a bit slow at first, but it turned into a great story.
I just finished FireFight, and I'd say it's a bit better.
Steelheart to me started off very poorly and got a bit better at the end.
Based on the list of books you provided, you seem to have very similar tastes as me. Personally, I would go a different route and read something that
I second those remarks about Durham's Acacia trilogy. I really wanted to like it, but the plotting was pretty poor in the end, the characters felt underwhelming,
I enjoyed Tad Williams' The War of the Flowers. It is definitely a standalone. I also heartily second Abercrombie's Best Served Cold, And Kay's Tigana