The author's own source now says the following:
As I have said in the past, these rumors come and go and it's hard to justify reporting on every one. But when I approached a trusted source of mine regarding them... I was surprised by the answer, to say the least.
Essentially, my source has confirmed that the increase in GPU clock speed is 100% true, with the increase happening in direct response to the PlayStation 4. The increase has been a reality since before the reveal, as they have "been reacting to Sony ever since the first leaks of both systems." The news of this bump in clock speed was announced to first parties only, as they "actively spread disinformation to 3rd parties just before reveal to prevent leaks."
This is where things start to stray from the original rumor though. When asked about the increase in RAM (from 8GB to 12GB), the response I obtained was simply "I have heard nothing like that, the development kits have 12GB of RAM, but as far as I know the retail kits are locked in at 8GB."
The source also went on to state that "it wouldn't be much use given the actual speed (of said RAM)." As for current projects, they also are "too far gone for a bump to be beneficial" as many developers have been developing for the currently announced set of Xbox One specifications. He did mention that the possibility may still be there though, as the increase in RAM would help development of games 2014 and beyond when taking second screen gaming into consideration - something many developers have been focusing on.
But what about poaching developers for suggestions regarding the increase? Well, from my sources understanding, Respawn Entertainment may have been the ones lobbying for the RAM bump. This would actually make sense, as Respawn has been very clear and vocal about how the 5GB of RAM allotted for gaming on the Xbox One has already caused issues in development of TitanFall.
Like I said though, these are just rumors, and as the past has proven, rumors come and go while changing on the fly - please take all of these with a grain of salt.