I suspect some Evangelicals view the kingdom gospel as some kind of soft, fluffy, feel good gospel. Jesus loves the world, lets all do good deeds and all will be good. I sense some hesitation to explore it.
The gospel message they want to emphasize is the tough gospel with a greater emphasis on sin, hell, God's holiness and wrath. If you want a serious gospel, you don't want to stray too far from there.
But please consider another way to look at it.
The gospel of the kingdom, as I see it, is a get your hands dirty kind of Gospel.
It is not an academic gospel where you accept a certain set of truths and the rest is up to God. Is is not about believing in God, saying a prayer, and waiting for better days in heaven.
There are two kingdoms at war!
Pick your side!
Put on your armor!
Get out of the grand-stands and join the front lines with your Lord!
This is how I see the gospel of the Kingdom that Jesus and His disciples preached.
I am not saying that Evangelicals do not get their hands dirty, or join in the battle.
My point here is that I'm not ashamed of the gospel Jesus preached. It is not a wimpy gospel.