It wasn't until Todd took over that Kasper got "low minutes". Until then he'd been getting typical third-line usage, about 14mins per game IIRC most of it at ES. He'd also had earlier stretches of playing with "skill" guys -- Kane, Tarasenko, Berggren -- and saw them waste numerous chances he created. One of the major differences now is that Todd has reduced third pair and 4th line minutes while increasing minutes for the top guys. Kasper was a victim of that early on, his minutes on 4th line dropping for five games to 10 and then a season low 9:16 in the win over Winnipeg. That stretch was what fuelled the whole "he's going to get scratched soon and sent down to GR to learn how to shoot and fight" thing. Todd had made it clear he was going to experiment and evaluate guys and eventually Kasper got his chance on the top line after Veleno had his turn.
The Wings have seen all year, in flashes during games and even practices, that Marco is an NHLer with underrated skills. They've known that all along, from the time they drafted him, but that it would take a while for him to figure things out in the NHL. Struggling at times as a 20yo rookie C was to be expected and part of the reason for his success now IMO is that he knows first-hand how hard it can be. He is obviously really enjoying how much easier it is with more space, a different job description and linemates who can scare the crap out of other teams.