Not really sure what the debate is all about, as any lens can show degrees of 'optimisation'. The mark one is a 'FX/full frame' lens optimised for the sensor sizes in their cameras at the time (DX), personally I view them no differently from telephoto zooms that are 'optimised' for the the tele end with weaker wide angle, or wide angle where the design was to have sharper corners and a weaker middle area. Can it not take pictures of areas in the wide end/ middle region of the frame? - No, certainly not, but the design was meant in a way that the lens performed better in some aspects than others.
Anyhow, s there maybe other reasons as to why the lens performs better on the D300 than D700. Maybe on the D700 there is a front/back focus issue? Or the generally theory that the 'sweet spot' of the lens i.e. the centre covers more of the 'frame' on a smaller sensor, so the usual softer corners are not shown on an APC-S camera- so for a shot frame similarly between the two, the DX yields better/sharper results across more of the frame.
Either way the mark one is awesome on the D300 I've used, and I'm sure the mark 2 is even better!