Hail and Brimstone campaigning may be the only way to wake up the voters, seems to have worked will with sinners.
All the critical issues are laid out for Trump to address and gain more support: immigration, terrorism, the economy, H1-B abuses, bad trade deals, the growth in welfare due to a poor economy, and on and on.
He can criticize Carson and Rubio on their kooky and dangerous views on immigration and other issues, even more so after the Paris atrocities. He does not need to resort to personal attacks that turn some of his supporters and potential supporters off.
Teddy Roosevelt: “Walk softly and carry a big stick” comes to mind...