That's what happens when you don't force him to do the work of two players. It's testament to his fitness and attitude that he wasn't badly injured last season, which could have had consequences at this time in his career. It really was atrocious management by Robson, I don't think it can be overstated. When you're not arriving late to every tackle and not really having to worry about where your midfield partner is, you're timing has a far greater chance of being successful. Not only that, but the increased efficiency means that you make better decisions and gives you more time on the ball, so it's no surprise to see him deliver telling crosses from space. He'll still tire in games, I'm sure, and his style of play will always result in bookings, but he's been good at managing that throughout his career and will continue to do so. He's a very good SPFL player that I reckon has another season beyond this one at the level he is now.
Edit to add: it was very frustrating to hear "the legs have gone" nonsense from our own fans last season, without the basic understanding of our team setup. It's not always clear on the telly I guess, you might just get an angle of Shinnie arriving late constantly, but numerous folk at the game could be heard questioning the player over the manager.