It seems odd that arbitrarily anything can be an 'artifact' if it's old. The guilloteen that killed Maria Antionette? Why? Also, how is it that there are all these things that pop up all over the place, and yet no one seems to know about them? I don't know that a bad guy is necessary in a show, but some kind of rival group that is also hunting the artifacts might make things more interesting.
If you like Warehouse 13 even a little, I highly recommend searching the internets for a Sci Fi miniseries called The Lost Room. It's about 6 episodes long, I think, aired in 2006. The gist is there's several artifacts that have power. They are common every day looking items like a comb, scissors, a pen, but have completely random powers (the Watch instantly hard boils eggs, for example). The main character is a police officer who gets The Key, which can work on any door with a key hole and always o pens into the motel room all the items came from. However, his daughter gets trapped in the room, so the police officer has to try to solve the mystery behind these items to try to get her back.
Great show, I wish it became a regular series.