Currently, without other range 10 spells to support it, casting Moonlight Ray at range 10 is not a significant benefit outside of kiting situations (and if you're successfully kiting then damage does not matter that much anyway). With range out of the picture, the important difference that remains between Moonlight Ray and Searing Light is area: Moonlight Ray is a beam, Searing Light gets a DoT instead. The thing is that the DoT is huge, more than the base damage of the spell, and once you get Spydric Poison and/or Circle of Warding it's pretty easy to leverage. I think it's a lot better than Moonlight Ray's beam. If you want to hit a lot of things at once, both the Sun and the Moons have better options.
I don't think perfect symmetry is required, but between Searing Light being better in most situations, and the Light tree, the Moons are handily outclassed right now.
By the way, while we're on the subject, I'd like to get the lore of Maj'Eyal's astronomy straight. Anorithil tree descriptions mention a singular Moon. The Pendant of the Sun and Moons mention, obviously, multiple moons, as does Heavenly Attunement. The question is, do Anorithils worship more than one moon? How many moons orbit Maj'Eyal? These are important questions.
