Things that have made Smith better this year:
Hunt is such a threat to rip off a first down that the defense has to account for him no matter the down and distance. It opens up lots of options for the Chiefs' complicated offense.
Hill is the defense's worst nightmare. Just being in motion draws an extra defenders attention. Notice where the safety is playing with Hill in the lineup compared to where they did with Maclin. Like Hunt, Hill opens up the play book even when the ball isn't coming his way.
Mahomes seems to have lighted a fire under Smith. Maybe not the competition for the starting job, but just the creative throws while on the move and the deeper passes look more like we expect Mahomes to be than what Smith was in past seasons.
Reid has been exceptional. He has brought in and used the tools to make this offense very hard to cover. Those who think the Chiefs took a step backward when Maclin was let go just aren't paying attention. They are making more first downs, more 20 yard plays, keeping the defenses off balance, and WINNING. Injuries haven't killed the offense yet and the defense is making do without Berry. Give credit to the coaching and planning.