I think you guys are giving Miroku too much credit. Granted, it's been a long time since I've seen Inuyasha so I can't say for sure, but as I recall all Miroku has going for him is Wind Tunnel and some other decent spiritual techniques. Other than that he's a slightly above average human. In terms of speed and power he's way below Neji and the only way Neji loses is if Neji foolishly stands right in front of Miroku without moving and if Miroku uses Wind Tunnel right off the bat. It's not that Miroku can't win, but the idea that he wins for sure ignores his massive speed disadvantage.