I agree, but does it MANDATE a sermon EVERY Sunday morning? And really, Is this passage not primarily about the informal preaching of the gospel that an evangelist does?
I will add that my pastor his heavily influenced by reformed teaching and practice (as am I), so it will be interesting to see if he would even consider this idea...I will find out sometime this week and try to remember to let you all know his reaction.
My understanding of Reformed policy is that the regulative principal of worship rests heavily on the primacy of preaching. It also asserts that only those things which are expressly commanded by God in Scripture are to be allowed in worship. That means the reading of the Word, the preaching of the Word, prayer, singing and the Sacraments are essential elements of worship.
I would be surprised if a reformed-leaning pastor allowed preaching to be sidelined by reading. Just as they would not allow preaching to become secondary to singing, as is often the case in many other churches.
I would imagine a special service, not a main Sunday worship service, may be allowed for what what you are asking to do.
There is nothing informal about evangelism. Preaching is preaching. It must be done with careful and prayerful dedication to remain true to the Word as God inspired it.
Is preaching a "mandate"? I would say....yes, most assuredly. I find no example in Scripture where God called a man to go and read. Why?
2Ti 4:1 I solemnly charge you in the presence of God and of Christ Jesus, who is to judge the living and the dead, and by His appearing and His kingdom:
2Ti 4:2 preach the word; be ready in season and out of season; reprove, rebuke, exhort, with great patience and instruction.
2Ti 4:3 For the time will come when they will not endure sound doctrine; but wanting to have their ears tickled, they will accumulate for themselves teachers in accordance to their own desires,
2Ti 4:4 and will turn away their ears from the truth and will turn aside to myths. (NASB, emphasis mine)
Preach.....because a time will come when men will not endure it. Why then should we suggest, imply, or infer that to not preach is ever OK?