When we look at Jesus Christ's earthly ministry we see quite a bit of teaching. While some of it contained back-and-forth conversation, others of it seems to have been mostly monologue in nature. The Sermon on the Mount is a good example of this.
I've heard Christians use the Sermon on the Mount as evidence for modern monologue preaching. The thinking is that "if monologue was good enough for Jesus it must also be good enough for us." This is problematic for a couple of reasons. First, Jesus was teaching people who were interested in him but were not yet his followers (in the sense of understanding the gospel and being indwelt by the Holy Spirit). Because of their lack of understanding, Christ sometimes needed to monologue.
When the church gathers today there's no need for monologue. This is because those present are all able to teach one another and should be doing so. All are indwelt by the Holy Spirit; each can edify another through personal instruction. Monologue is not necessary and can actually stifle body growth.
Second and more important, Jesus gets to monologue because he is God. He alone has a special status within the church. He has insight we could never have. He knows the standards he expects. He teaches the beliefs we should all have. I'll say it again: Christ is Lord and God.
No one in the body of Christ is Christ (only the Head is). None of us should teach as Jesus did just because he did it. Jesus did many unique things. Who are we to teach as he did as if we have the right to monologue? It's actually fairly arrogant thinking.
The church has no need for lecturing. Rather, the entire body grows together most effectively when all take on the responsibility of teaching each other. This form of mutual edification is more than suggested in scripture; it is what we should be doing. Through body life we all gain from the knowledge and experiences of everyone else in the group. Group knowledge is far more accurate and full than individual knowledge.
Jesus alone gets to monologue. We don't, nor should we.