The Utes began 2018 with Taylor's spread-to-pass RPO-centric offense. The one where Moss barely touched the ball for the first third of the season. The offense went through a pretty significant reboot and emerged as more of a spread-to-run power offense. That worked until Huntley and Moss went down. Without a great RB, things were reshuffled and the RPO-based concepts became more prominent in the final third of the season.
Ludwig isn't a "system" guy that runs his system and then recruits players to fill his roles over time like a Leach (or Troy Taylor). Although Ludwig's more of a power spread-to-run guy, he's flexible IMO that limits his ceiling, but because he adapts to the team and personnel, he can get off to a quicker start. Sort of the same deal as ARod.
Utah's going to fall back on the same Spread-to-run concepts that Harding was using mid-season. Harding is from the Pinkel tree who learned Spread to run from Urban. Ludwig has inherited a Meyeresque Spread before. It's not a stretch for him and his tendencies. Utah will have a more established, focused scheme game 1 of 2019 than the mess that resulted from the TT/Harding-KW tug of war of 2018.