Yeah, when you look at Fate/Zero, you can really tell that there were characters that Urobuchi was really enthusiastic about and characters that are just there, whether because they were already part of the story or he couldn't come up with anything more than a stand-in. There are parts of Fate/Zero that are amazing, and there are parts that are just utterly boring and forgettable, and sadly a lot of the latter deal with the franchise's established cast. Urobuchi's got a number of strengths as a writer, but I don't feel like Fate/Zero is one of his better works by any stretch.