I'm a little confused about this statement. Healing Word and Inspiring Word are exactly the same, mechanically speaking. Did I miss something?
Clerics get to add their Wisdom modfier to any hit points regained from a Power that has the Healing keyword - meaning that they usually heal 3 to 5 more hit points per use of Healing word than a Warlord does with Inspiring Word.
This also really adds up over the course of a combat when multiple Healing keyword powers are used.