Warwick Davis is fine as Willow, everyone else is okay but it feels like someone was told the plot of Lord of the Rings in a half hour meeting, shown a couple of Alan Lee paintings and told - give me something like this but don't infringe too many copyrights.
I'm not convinced either Lucas or Howard actually understand the fantasy genre. It does have its moments but no real sense of wonder (now that the morphing scene is old hat.)