Out of curiosity, how many people have actually used any artifacts in their game so far? I love that they're using the affiliation system from 3.5 with artifacts, but +1d10 for a level up makes it seem like a character might very quickly find himself with a pleased item, which is pretty significant, given how few (official) ways there are to lower concordance.
Well, I think its clear that WotC wants PCs using artifacts to consistently have a concordance score near the higher end of the spectrum, since that makes the artifacts more useful to the PCs as magic items and to DMs as plot devices and NPCs.
Then what's the point of having a concordance system at all if by design they skew it so that PCs pretty much automatically have happy items?
Well, it gives the PCs agency when dealing with the artifact; otherwise, it really is just a plot device that operates at the whims of the DM. It also allows PCs to really bungle their interactions with the artifact, which introduces an element of risk to the proceedings and makes it behave more like a NPC. Finally,a sliding concordance score allows the designers to incorporate an equally sliding scale of cool powers.