I understand your thoughts because it can be frustrating having no drop. Basically if you want paragon levels then the 35% xp the ring gives is great and you see if you can get a good one.
If you are not interested in paragon then the guaranteed xp on ring has no appeal. Farm wherever you want and when a ring drops it is as good as (or better because can get 6 properties) the hellfire ring and thats that.
Leoric's signet sells for millions (purely based on it's xp bonus) so I guess the Hellfire ring is a long process but guarantees you at the end of it all to get a +xp ring.