I watched him plenty, this version we're seeing is absolutely nothing like what he produced for Dortmund. He was much more direct, constantly running at his man or bringing his overlapping full back or no.8/10 into play and he scored quite a few goals.
Bundesliga is a lot less frantic and chaotic than the PL, defenders are slower and the intensity is lesser so he didn't get pressed as much.
I think we'll look at moving him on in summer, or give him one last chance next season, which needs to be a wakeup call to the club and new owner that they need the best in recruitment and talent identification.