Weigl is great, across all the top leagues there could be a decent argument for him being the best signing of the season, Dortmund got him for dirt cheap and he's become a key player for them already. He's an incredibly active central midfielder, runs like crazy and does a lot of dirty work the times I've watched him, he's a very mature player for his age. I'd see him as a like for like replacement for Fernandinho in the future rather than for Yaya though, he's not really a playmaker per se. I don't see him coming to us already though, he only just arrived at Dortmund this season and slotted in perfectly, we'd have to do a lot to get him.