From someone at thinkpads.com:
"The T60 has increased power requirements, which made Lenovo make the move to a 20v power plane, from a 10.8v power plane with the T4x series. By definition, Voltage is easier to push through a circuit than Current, so it makes for a better PWM circuit design. For 90w on a 10.8v power plane, they would have had to push ~8.4a, which makes for a larger, hotter power brick. With 20v, theyre back down to roughly 4a, which is what the T4x uses."
As long as the future processors have the same power requirements as the t60, new accessories (like power adapters and docks) will be compatible with the t60, but won't be compatible with the t4x's.
So, for future docks etc to work on the t43, they will have to make one retrograde to fit the t4x's. However, right now, and I'm sure for the next several years (at least), the availability of docks and accessories that fit the t4x power requirement far outnumber those fitting the t60's, especially if you're looking on ebay etc.
Overall, I wouldn't think of this as a reason to look more favorably on the t4x or the t60, but really as a minor detractor for each. I don't think it would cause any real problems for either side, though.