I can understand being a little disappointed by this change, but come on, get real. USGBC and LEED have created this entire business opportunity that you're taking advantage of, and you think that $1,500/year for preferred rates is unfair? 
Yes, it's a huge leap from $300, but that was a ridiculously low rate for people whose business is built on LEED. The fact is that USGBC is no longer bringing in lots of money from AP exams and reference guides, so they have to generate revenue somehow. This seems like a pretty fair distribution of costs to me, aligning those costs with value people get from the organization.