[xzins]

There is nothing that says a sermon or service cannot be designed to feed both ends of the spectrum.

HOWEVER, there is nothing wrong, if there are multiple services, to have them focused on different things.

There's nothing unscriptural, illogical, or immoral about it. It's one of those do it if it works for you kind of things.

After all, we are free.

[George W. Bush]

There is nothing that says a sermon or service cannot be designed to feed both ends of the spectrum.

As so many Spurgeon sermons amply demonstrate.

However, Spurgeon wasn't seeker-friendly in modern terms. And he did not neglect teaching strong doctrine in his primary worship service.

I think the primary emphasis of your main worship service should be to build up your flock in doctrine. Your secondary purpose is evangelism to lost souls. But if you build up a sound congregation, then converts will follow as a result. People will be inspired to lead more godly lives and to witness to or be an example of Christian life and this will do more for your church than putting a preacher in the pulpit as the church's Lone Ranger, emitting yet another seeker-friendly message which puts the faithful to sleep.

There is no avoiding the need for doctrinally sound sermons at your primary services.