Magician was super popular at the time, but having already read Tolkien, Anne McCaffrey, Moorcock and a few others I found it more of a join the dots exercise spotting where he pinched pretty much everything from. It was like reading a whistle stop tour of fantasy fiction from the 60s and 70s. I did read some of the later novels. The sequel where Midkemia was invaded by a blatant clone of the Empire of the Petal Throne from Tékumel was fun.
That might come across as faint praise, which it is a bit, but like a few novel series of the time, it was a toy box of fantasy fun. Most of the readers of novels like this were never going to wade through all the source material, but here all the basic concepts were in compendium form. They certainly had a niche to fill.