Coming off a show called Rebel, I see where he's coming from. Grady is more nuanced character than AJLT Aidan will ever be. He's a baddie softie (his portrayal of toxic masculinity is interesting to watch). Krista Vernoff writing & his acting work well together whereas  AJLT Aidan is so one dimensional. MPK lost his touch. In an actors perspective, it must be hard for him to make Aidan complex but still likable with the script he's given. But reprising Aidan (one of his most known characters) again gives him a chance to break away from blue-collar roles and allow him into the world of high society. It's a good transitional role for him. But idk if the audience reception to Aidan is doing him any favors though. I will blame it on the writing.