I agree, the average user won't need to root. I consider myself a slightly above average user when it comes to phones (I've always been into customizing computers). I rooted and installed Liberated Froyo, and also tried out CM6, and wouldn't dream of going back to stock. Unless of course we get an official Froyo update, and it gets rooted
Anyways, I never thought my battery life was too bad on stock (I had most syncing off or set to 3 hours, and gps and bluetooth turned off). But now on Liberated, my battery is even better.