Anime features and extended OVAs tend to get a bad reputation, and I'm not exactly sure why that tends to be the case. I think in part it has to do with the issues of canonicity, and the fandoms obsession with canon, as well as the nature of the promotion. If this was labeled "Bonus Episode" rather than movie, i'm sure you would see a score point boost alone. There is really nothing here that significantly differs from the actually series itself, and for what is essentially 20 minutes worth of content, it really didn't feel very different from the main series?
It could be the English voice cast in the Media Blasters version, which is undoubtedly how majority of the watchers of this are consuming it, but it should be noted in the Japanese version the cast is their normal cast. Shoakura is also Rica Matsumoto, who is mainly known as Ash, but also voiced Fusuke in Ninku (the other movie produced and premiered along side this one in the DVD). So most of the voice acting problems definitely do not exist, but since it's pretty hard to find the funimation version i doubt anyone saw it.