As to the Shadows and Vorlons reacting like whiney children at the end - I think, if you look at it, the Shadows' and Vorlons' behavior was always
childish. They were playground bullies, control freaks, always wanting their own way no matter who they hurt.
And as to the end of the war being anticlimactic - well, it was apparently good enough for (here I go) Deep Space Nine to rip off. After all that fighting, Odo just talks
the "Female Shape Shifter" into stopping? Hm. Original.