The document I posted about planned improvements is dated July 2012. The document is published on the Westpac Stadium website http://westpacstadium.co.nz/master-plan/
I doubt anyone cared enough before now to put much thought into it, but since we're discussing facilities, it is relevant again.
In regards to the use of Petone Rec as a training ground, I didn't see anything specific in the sketch for training facilities. That might be in the final build plan, but seems a rather important aspect to the overall design and use of the space.
I would expect if Phoenix invest money in a quality training pitch they don't want Joe Public walking the dog or riding their bikes all over it when it's muddy. Or they would end up training on Naenae 1. Which would probably explain all the fencing around Newtown 2.