Not sure I agree with that, its a pretty inneficient rule. If your DM enforces the "long day" (i.e. cant extended rest just anywhere/anytime) the amount of hit points you get from each healing surge and getting the most out of them becomes really important.1.) The cleric should only use HW on a character AFTER they have second winded.
"Healing word" Gives a not too shabby bonus (our L. 21 warlord gives 5d6+6) per use, meaning they should (by my logic) be used in preference to un-augmented heals (like Second wind).
Mind you, Im interested to here you rational, maybe there is a perspective I havent considered.