I was just on the phone with a WDW agent attempting to book my trip through
AAA (yup, I was on the phone, not the AAA person...because pretty much all she knew was that Disney World was that place with Epcot

)
Anyway, the person on the phone said that they just changed which rooms are preferred. He told me (so this is NOT official) that now ALL poolside rooms in the 50's section are considered preferred

- not just the ones closest to the main building. I didn't ask specifically which rooms were now preferred in the 70's or if there were changes in the 60's. All rooms in the 80's and 90's are still standard.
Just thought you all might like to have this info in case it changes whether or not you want a preferred room. Also, maybe someone can confirm or deny this. The cast member seemed pretty knowledgeable, but you never know!