I would submit that a buff of artifacts due to the coming of Imbuing is very unlikely.
I can certainly see your point, which is that many of the artifacts have properties that are now seem under-powered, and will seem moreso once Imbuing gives us the ability to make customized items.
The first reason why the artifacts are unlikely to get a boost is that, even though it may not be a "big project" per se, it may be bigger than they can handle right now with everything else there is to do.
Beyond that.....While I certainly see your point, I'd also like to submit that, even in their present form, some of the artifacts are under-rated.
I am still seen using the Blade of Insanity on occasion, though I have other weapons that are far better. There are some situations where the good ole' BoI just works really well. (Not to mention that mine has a cool, inscribed name.)
The Legacy of the Dread Lord has FCR 3, a property not normally found on weapons at all. FCR 3 may be useless to hardened gamers who have spent a long time building up suits that already incorporate 2/6 casting. But to a newer player who hasn't yet been able to find a good ring/bracelet combo yet, it's potentially very useful. Also consider that Orni + Legacy = 2/6 casting by themselves, freeing up a ring slot. The idea of a warrior-mage running around with a Ring of the Vile in the ring slot has a kind of intuitive appeal to me, though I know that better setups are available.
Jackal's Collar is still useful and my instinct tells me it will remain so.
Holy Knight's Breastplate has always sucked, so nothing's changed there.
Ring of the Elements is useful for a luck-tamer, who may otherwise be forced to sacrifice resists.
Frostbringer may suck, but it still doesn't suck as bad as people think. Back when I was an archer, I discovered it was a superb champ spawn bow. Frostbringer + GM Focus = 20 Stamina Regen, plus whatever you can get from your other items. And many champ spawn monsters have low cold resist. So it's a nice combination.
And finally....Imbued items will be non-PoF-able. Artifacts are PoF-able and are likely to remain so.
Let's face it....Artifacts are no longer for hardened, experienced players. They are no longer the best items in the game, they haven't been for awhile. Rather they are for middle-end players and/or upper-end players who aren't willing to spend a lot of time putting together a suit. They afford a certain predictability. You know what properties they'll have (they have the same every time).
All in all....I do not think a buffing of artifacts ie likely to happen.
-Galen's player