i have a similar issue. I also ride close to as much switch as regular... with similar - but not as aggressive a setup on the angle... also using burton ruler boots (2011 model i think...)
I found that my boot started to press into that area just below the front foot's umm... under ankle bone... bone.
I've wanted to just heat up the boot and push that area out more. Or even reduce some of the padding/pressure in that area inside the liner... not sure which to try - or if both are a bad idea, tho the latter would be more permanent for the burton rulers.