The ingredients for Daedric are more rare.
I think that's the reason it's top tier.
But the difference is so minor, that it really doesn't matter.

Also, Daedra items have always been the most unique and powerful stuff (in most cases) So it does fit the Lore as far as I know.

But if you want to make a mod to change, then do it. There's no need to worry about what other people want
If it shapes your game how you want it, then go for it.

Well since we dont know the actual strength of a Dragon's bones it is hard to say. If you want lore-friendly then you shouldnt be able to make Daedric armor anyways because it requires an eclipse or something. Also each piece is supposed to be possessed by a Daedra who desperately wants out. So lore-wise Dragonplate would be much easier to forge based on convenience (more so than it is now) but really neither should be so easily craftable. You have to think about it in terms of working these materials. Can any smith make armor from Dragonbone? Unlikely since nobody has access to dragons (since they have been gone for a very long time) so it is would be rarer to know "how" to smith Dragonbone while it would be rarer to have the conditions correct to smith Daedric

The Daedra are et'ada that did not sacrifice part or all of themselves to create the Mundus like the Aedra, and also did not go "screw this i'm outta here" like the Magna-Ge, so naturally anything arcanely made will be imbued with a lot of power. Especially if it came directly from a Prince.

Dragons (including the Dragonborn), on the other hand, are Children/Subgradients* of Akatosh/Auri-el/Whichever Time God pantheonic aspect you want to refer to him as, who was one of the Aedra. Though their physical forms are powerful, they are still technically a part of the Mundus.

* = It's theorized that when you are absorbing a dragon soul, you aren't necessarily "devouring" it, so much as piecing another piece of the fragmented soul of Akatosh into your own. The swirling glowy mists during such an event are literally the soul energies of Akatosh himself, svcked into the Dragonborn's body (IE: the nearest draconic soul in a not-ruined corporeal form) like a regular soul is into a soul gem when trapped.

essentially this.

Daedric is also made from infusing the essence of a Daedra into Ebony which is consider to be the blood of Lorkhan or "God's Blood" hence why ebony is only found in High Rock, skyrim and a large portion of Morrowind. Because that's the path that Lorkhan's heart flew when Auriel shot it from on top of Ur-tower or otherwise known as Adamantine tower in Balferi in High Rock.

I think my favorite armor types are Daedric, Ebony, and Dragonplate. I think they are the best quality.

by the time you reach 100 smithing you are way above the armor cap anyway so really it does not matter.

"Realism" is an odd thing to look for when you're talking about Dragon armor and an armor where they shove the Deadra in and you can still hear the Deadra's screams.

Also this.

Exactly. Any armor in this game can reach the armor cap. It's all about personal preference anyway.

I don't understand why it matters. Both armors are stupidly powerful and hit the cap relatively easily. Daedric's meager few points over Dragonplate really isn't that big of a deal. Not to mention Daedric being more powerful makes sense anyway.

It's your game and your right to modify how you like.

I think of it this way: Sometime in the future dragons parts may be very rare or impossible to find. Only the armor made by the dragonborn will survive and will be an epic find in the next ES.

So the bones of giant flying shards of a dead god vs. The blood from the heart of another dead god infused with the essence and blood of demon from an other worldly plane of existence? Nothing is realistic about this