I wish someone made a mod that would remove skill xp gain from repeatedly enchanting similar objects with similar enchantments. I mean, an arch-enchanter who built his career (and personal fortune) entirely on Muffle jewellery is plain ridiculous (yet entirely plausible in Skyrim).

I realise my proposal is a rather radical one: no skill xp unless either enchantment type AND/OR base magnitude, or object type is different. To prevent the sheer number of type/material combinations from defeating the original purpose, it should be type, not type/material.

Thus, having just produced, for example, a Fire Damage effect Iron Dagger, enchanting a Fire Damage effect Steel one won't give you new insights into Enchanting. However, it should be enchantment type AND/OR strength, so, having raised your Enchanting skill enough to produce +15 base magnitude Fire Damage enchantments instead of +14, you will gain skill xp from enchanting another Iron (or any other) dagger with the same nominal enchantment type.

Obviously, it would help to have a helper mod (something along the lines of http://www.nexusmods.com/skyrim/mods/32380/?) to make it clear whether a particular combination has already been "used".