... lowering the nose does reduce ROC .... but its pretty insignificant in the grand scheme of things ...
Agree 100%.
Unless you actually throttle back while lowering the nose to look out, the full throttle engine will continue to increase your energy. True, while the nose is down you will be speeding up instead of climbing, but once you lift the nose again that extra speed gives you extra ROC till you get back to best climb speed.
I admit you will have left the 'maximum excess power' speed for a short while, but the curve is pretty flat on top, so I can't see it amounting to much.