I'm in complete agreement about the Willows. I never built one of those monstrosities and they're certainly not in any way essential like various advice would leave you to believe. From the get go they give worse mana per square than more than one of the smaller standard mana producing buildings. The culture may be better if that's of particular importance.With Spire sets and event buildings, those whipping willows are junk (nice culture, but too big)... those poor treants... that's treant cruelty!!