Well, since he has such a national following, we have every right... actually a responsibility... to examine his teaching and offer refutations.
Everyone seems to paint horns and a tail on Joel, but I suspect he is sincere and I have no reason to doubt his salvation.
Sincerity is not an excuse however. Like I said, time will tell. The initial note is promising. If he continues in the direction that note sets, I will 'rejoice and be glad' -- but for now I just have hope that he will do that, until he proves me wrong.
So refute his teachings if they are in error. Offer sound doctrine. But don't tear him down for the sole purpose of watching him fall. It seems to me that the biggest complaint most people have is not that his doctrine is wrong, but that it is supposedly "incomplete" or that his emphasis is different than you would preach. It's not the "whole" gospel. Whatever. What percentage of churches in the world preach the whole gospel? I'm sure Osteen's church teaches more gospel than you will find in many of the traditional churches.
Do you spend this much time attacking the perverters of the gospel that have turned over their pulpits to homosexuals and atheists? Why this obsession with Joel Osteen and Rick Warren? At least these guys are pointing their flocks in the right direction. Many of the traditional Churches are leading their flocks directly on the path to destruction. Where is your outrage there?