If you recall, at the end of my last Legion post, I was discussing my concern for hybrids being able to maintain two artifacts. Some nights you are going to have too many tanks or too many healers online and you'll need someone to switch to DPS. Most players want to do well in whatever role they are be performing and having a decently progressed artifact looks like its going to be key to that.
Blizzard recognized this issue and today, Watcher gave us some details about their proposed solution called Artifact Knowledge. Artifact Knowledge is something you build through Order Hall missions and works as a kind of multiplier to your Artifact power.
This system is key to the pacing of overall artifact progression, and to making it easier for players to maintain multiple artifacts if they so desire. For example, at Knowledge Level 7, you would be earning Artifact Power at over triple the base rate. Thus, if you wanted to switch to a spec you hadn't yet tried at that point, you'd find yourself very quickly able to get that artifact up to par with your primary one. (emphasis added)
This is exactly the kind of thing players needed and I'm really glad to see this system has been developed. There is still the open question as to whether we will have access to all three Artifacts (one for each spec), but the Artifact Knowledge system demonstrates the developers have thought through some of the potential issues with Artifacts and are working on solutions. If they saw the issue with maintaining multiple artifacts, I'm confident they've also thought about if players will have access to two or three of their classes artifacts. Demon Hunters need to not worry since they only have two specs and therefore two artifacts.
Where the Artifact Knowledge system doesn't help is your alts. Artifact Knowledge is tied to the character and it's not account wide so each alt will have to build it up for themselves. Most of my alts are pretty much one spec ponies so I don't think this will be a huge issue for me but for a more dedicated altaholic it may be something of a hurdle.