The issue with a hard rule of Raid > Named > Random is that it basically means that every chest is useless unless it has named loot.
DDO has almost always had something you really wanted to see in chests - +1 Vorpals at the 10 and 12 caps, +6 Con rings at the 14 cap, Wounding/Puncturing weapons and Holy/Silver weapons at the 16 cap, Superior Potency 6 kamas in the early days of the 20 cap, +3 tomes in the later days of the 20 cap, and Convalescent of Superior Parrying bracers, Primal of Superior Parrying shields, Obscenity weapons and Primal of Spell Proofing robes at the 25 cap.
This adds to the game as long as the items are rare enough that you don't get them all the time, but not so rare that they are never seen. The 14 cap worked well in that regard - people kept running Prison of the Planes for +6 stat rings and elite Litany for Superior Potency 6 items and for +2 tomes.
The present issue is that the best lootgen combinations are super-common, and they outclass everything that came before. It's not that they are 'just a little bit better', they utterly outclass older gear to the point that the Shadowfail loot changes effectively deleted all of the older raids and all of the 25 cap EE content.
I think that if item power level is measured from 1 to 10, 'random' loot should include items from 1 to 8. Named items from easier content should be from 2 to 9, and named items from difficult content 3 to 10. (I'm counting raid items as named items here - I see no reason to make a distinction based on group size, it should be based on content difficulty).