From what I remember it was possibly due to fact that roots on outside of pot were drying prematurely causing problems
This is the one that bothers me. I think the root-pruning from the fabric reduces the amount of soil that the biota like - gets too dry too soon.
But I did well with a 10 gallon square fabric pot in a crate. It's just a little trickier. Try harder to keep the outside of the rootball moist.