You hear about this all the time~some pastor and a dozen people start a new church and a few years later there are 1000+ members and it makes you wonder what's going on. Each one has its own story and would have to be evaluated on an individual basis. Is seeker-friendly strategies world conforming? Seems like it can be that way; Jesus nor the Apostles were particularly seeker-friendly by any stretch of the imagination, yet they did seek and save the lost. Seems like the opposite of "seeker sensititive" churches can sometimes be evangelical cloisters where we surround ourselves with people like ourselves.
Growth is often the measure of success but then too nongrowth can be worn as a badge of some sort of martyred obedience ("we don't grow in numbers because the world is so dark and lost", "we grow in spirituality instead of members"). The entire "church membership" thing is something of the devil I think in that it's not of scriptural basis. One is a member of the church by blood of Christ, not because some clergy deemed you fit to be put upon some congregational rollcall list. Yet that list again is the measure of success in the world's eye, and unfortunately in much of the church's eye...
The measure of success (and by "success" I mean God-blessed obedience) in the church is by obedience to His word and calling on our lives as a church~not by a mass of flesh that has signed up to a particular creed/doctrinal statement, but by a mass of flesh that has God's stamp upon them out doing the will of God for that body.
Repeating again:
Jas 1:26 Jas 1:27 KJV
If any man among you seem to be religious, and bridleth not his tongue, but deceiveth his own heart, this mans religion is vain. Pure religion and undefiled before God and the Father is this, To visit the fatherless and widows in their affliction, and to keep himself unspotted from the world.
And:
Mt 25:31 Mt 25:46 NKJV
When the Son of Man comes in His glory, and all the holy angels with Him, then He will sit on the throne of His glory.
All the nations will be gathered before Him, and He will separate them one from another, as a shepherd divides his sheep from the goats. And He will set the sheep on His right hand, but the goats on the left. Then the King will say to those on His right hand, Come, you blessed of My Father, inherit the kingdom prepared for you from the foundation of the world: for I was hungry and you gave Me food; I was thirsty and you gave Me drink; I was a stranger and you took Me in; I was naked and you clothed Me; I was sick and you visited Me; I was in prison and you came to Me.
Then the righteous will answer Him, saying, Lord, when did we see You hungry and feed You, or thirsty and give You drink?
When did we see You a stranger and take You in, or naked and clothe You? Or when did we see You sick, or in prison, and come to You? And the King will answer and say to them, Assuredly, I say to you, inasmuch as you did it to one of the least of these My brethren, you did it to Me.
Then He will also say to those on the left hand, Depart from Me, you cursed, into the everlasting fire prepared for the devil and his angels:
for I was hungry and you gave Me no food; I was thirsty and you gave Me no drink; I was a stranger and you did not take Me in, naked and you did not clothe Me, sick and in prison and you did not visit Me.
Then they also will answer Him, saying, Lord, when did we see You hungry or thirsty or a stranger or naked or sick or in prison, and did not minister to You?
Then He will answer them, saying, Assuredly, I say to you, inasmuch as you did not do it to one of the least of these, you did not do it to Me. And these will go away into everlasting punishment, but the righteous into eternal life.
This then is the essence of Christianity~not a mental assent to a list of doctrines, but the Holy Spirit's work in one's submitted existence, putting our entire life out there for Christ to use as He sees fit. Conformity to the world then becomes impossible as the Spirit moves Christ's Body to do the will of God. And that may very well get done in some aspect among the seeker-sensitive groups; I think though it would much more difficult, for in some respects those folks have already decided how the Body of Christ is supposed to act, and have become something of legalists in their own way..