Haha...your experience with the Casas sounds EXACTLY like mine!
You really just need to try on every boot you can in order to find the one that fits perfectly. I replaced my Casas with Salomon Ivys - LOVE them! Very comfortable, no pressure points, much more support, warm, etc. If you want an even stiffer boot, the Kianas are also very nice.
Salomon Ivy is amazinggggg. I've got a salomon ivy deck and I love it.
I personally have salomon everything except for my boots, I rock a pair of northwave Devine's.
I've never seen anyone with northwave boots, so I'd imagine they're tough to come across. I bought my boots from a friend of mine and they're amazing. I normally destroy my boots and have to get a new pair every season. I have about 6 pairs of snowboard boots sitting in my closet. My Northwaves haven't failed me at alllll. They've lasted me through 3 season, and I doubt it'll see many more cuz I rode the shit out of them. Very comfy, and very light.
I do not recommend burtons. I bought a pair of Burton Moto's a few years back and they didn't last me the entire season. I tore those things apart.