The word "missional" has been very in vogue in recent years. It doesn't matter if you're a liberal or an evangelical, baptist, reformed, arminian, or calvinist you can embrace the word missional. Perhaps that's part of the appeal of the word. I'm sure that's part of its appeal in my denomination, the RCA. We like it because we can each make it mean what we want and speak the same language while remaining distinct in the manifestation of our missionality.
But, personally, I'm not one to go for "container" words. By container words I mean words that sound nice but are actually quite empty and allow you to fill them with your own meaning. Missional is the paradigmatic container word. A word that can mean so many different things to so many different people is not one that I'm prone to put a whole lot of trust in.
Matthew 28:18-20 is the beginning and the end of the discussion on the mission of the church. "Then Jesus came to them and said, 'All authority in heaven and on earth has been given to me. Therefore go and make disciples of all nations, baptizing them in teh name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.'"
If your view of missional has this in mind then let's join hands in the labor of the Lord, brother. If not, then even if we use the same words we're not really speaking the same language.
Does Matthew 28 exhaust the idea of mission? No. But, if your idea of mission falls outside of those bounds you can be sure that it's not mission.