Unity depends on maturity
1Co 3:1 And I, brethren, could not speak unto you as unto spiritual, but as unto carnal, even as unto babes in Christ.
1Co 3:2 I have fed you with milk, and not with meat: for hitherto ye were not able to bear it, neither yet now are ye able.
1Co 3:3 For ye are yet carnal: for whereas there is among you envying, and strife, and divisions, are ye not carnal, and walk as men?
Eph 4:11 And he gave some, apostles; and some, prophets; and some, evangelists; and some, pastors and teachers;
Eph 4:12 For the perfecting of the saints, for the work of the ministry, for the edifying of the body of Christ:
Eph 4:13 Till we all come in the unity of the faith, and of the knowledge of the Son of God, unto a perfect man, unto the measure of the stature of the fulness of Christ:
Eph 4:14 That we henceforth be no more children, tossed to and fro, and carried about with every wind of doctrine, by the sleight of men, and cunning craftiness, whereby they lie in wait to deceive;
Eph 4:15 But speaking the truth in love, may grow up into him in all things, which is the head, even Christ:
Those responsible for shepherding by teaching should understand that to be "successful" each of the people he teaches should be like Christ. This is to be accomplished by teaching them to walk in the Spirit rather than the flesh.