I fish a lot of weighted flies, clousers, etc. and the lines that roll cast fairly well work better for me. I have slow rods and fast rods, it seems that modifying the casting stroke is also important. I've been reluctant to invest in any of the new full sinks because the cost prohibits experimenting.
The Axiom is said to be a real cannon, but many people end up overlining it. One effect of overlining is to slow the rod down and I suspect that is the end porpose in many cases. It might not be the White River, it might be that you need a faster rod to match your casting style.