I guess you played WoW (or another MMO) in the past, where stats were dealt with in a very precise way ? I did. In MMOs it is necessary to do that. To prevent inconsistencies and surprises. To make sure the players will always go hunt for that piece of equipment that is slightly better. To keep everybody motivated. To make minmaxing a game inside the game. To keep the threadmill running.
In a single-player game that is much less important.
Whenever I look at the gear that we can find in Skyrim, I don't see a consistent pattern. The items we find, or get as rewards, are usually not very impressive. Pre-enchanted gear usually has crappy enchantments on it. In the end, the best gear is the gear you craft and improve yourself. And that has your own enchants on it. Using enchanted gear for smithing and alchemy, and using potions to improve smithing and enchanting, will allow you to make gear that is exactly as powerful as you wish. (Potions of restauration are the big help there).
Personally I always thought that Daedric items are the best items.
But you seem to think that Dragonbone items should be better.
Maybe you are right. But it hardly matters. If you really want, you can improve any item to be exactly as good as you want.
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From these pages, it looks like you are correct:
http://www.uesp.net/wiki/Skyrim:Daedric_Sword#Daedric_Sword
http://www.uesp.net/wiki/Skyrim:Dragonbone_Sword#Dragonbone_Sword
Maybe you have some armorsmithing perk that allows you to improve Daedric gear more than you can improve other gear ?