OK, call me a crank, a malcontent, a hypercritical reviewer with a small, crabbed heart. But despite all its earnestness, despite its heartfelt message, which an environmentalist and concerned parent like me should embrace -- in brief, that nature is good for children -- Richard Louv's plea to reengage our children with nature left me strangely uninspired. As with all good ideas, it is one worth repeating, but I would have been happier reading Emerson, I think, for the lesson. Last Child in the Woods, by Richard Louv, Algonquin Books of Chapel Hill, 336 pgs, 2005. Louv, a columnist for …