I totally agree with this, and it marks the first series for me a bit. The setting and concept are great, but Joe is a pastiche and until they calm his character down he's not very believable. He gets too much screen time and the expense of other, better characters. As you say, it's not bad, just it hasn't grown into itself. The last series is both excellent and poignant. The group always being just a bit too early with their ideas creates a sense of innovation but it's also tinged with failure which I think really works.