I'm in the same situation. I padded the cuff last year with a wrap all the way around and put in shims all over the place. Problem is at end of last year it still just is loose when I really need them. Easy trails are fine-can ski with the buckles undone, but on choppy stuff or hard stuff even all buckled up I feel like there's no control sometimes.
I went in to a boot shop (a very good one) and started up this conversation. Started trying on boots. Nothing really felt that much better. We were thinking foam. Towards the end we started trying another shell size down. I was thinking no way because last time I went down a shell size, (10 1/4, 10 3/4 feet in a 9 shell), and it took a lot of work to get it to work-stretching, grinding etc. The surprise was that it looks like the smaller shell size (26 or size 8) is going to work with some serious stretching/grinding etc. Although my toes were jammed and it's hard to accurately tell how they fit, you can definitely tell that the whole foot is much better.
My suggestion is to go try a shell size down. It's much better to make a small shell fit than fill in with foam. Foam isn't the be all and end all to every problem unfortuneately. A lot of times it doesn't work well.