I've been researching Daedric vs Ebony weapons, and I've found that a lot of them have a -1 or +1 variance, the ebony is almost always lighter and does equal or higher damage. This is just what I've found on the Wikia. My guess is that Beth did this to force the user to think outside the box when equipping weapons and armor. Does anyone know why they really did this, though?

My guess is that some people consider Daedric to be evil since it's 'powered' by the heart of a living humanoid so Ebony was an equal-ish option for good and good-ish characters.

I actually think this might be the reason. As buckom says, there are many players who don't like the look of Daedric because it looks "evil." I think Bethesda is probably aware of this.

If you are going for stats, ebony's delta may in many cases be better than daedric like you indicated- because of weight. Since you are smithing- ebony can match daedric in Armor
Value max quite easily, can get so near the damage value of daedric that the difference is negligible, and all for the savings of a perk.

This is the same reason that skyforge weapons > elven.

Daedric weapons are forged from Ebony. Case closed.

I use Vokun, a Dragon priest mask with my Daedric. It get rid of the whole evil look a bit. I don't like ebony, my follower will soon be wearing Dawnguard Heavy armour. I need to get the full set. I haven't reached expert level conjuration yet, even though I summon a shock atronarch quite a bit.

But for a character without maxed heavy armor, daedric has a higher armor value than ebony armor, right?

Yeah, Ebony and a Daedra Heart.
That's like saying that Iron and Steel are the same because Steel is made with Iron. Duh.
Or Iron Banded is the same as Iron because they both use Iron.
The Daedra heart is supposed to imbue the metal and make is stronger, the way that Corundum makes Iron Banded and Scaled/Steel Plate armors better.
Not to mention, Daedric Armor is 10 levels higher, therefor should be made to be better.

Yeah, but most consider the difference to be negligible. Plus, you can easily pass the cap with either.

I'm actually happy to hear that...because daedric is too bulky for my tastes. I don't know if I'll switch my companion back to ebony now though...