Well, I was hoping for another "Arcanum" myself but if they did do one it wouldn't be a real sequel (more Arcanum with better technology) but a modern re-envisioning of it that will probably simplify everything down to the point where it wouldn't satisfy me at all.
That said, while my sources aren't great, some of the scuttlebutt in the MMO scene is that this is being done for two reasons. The primary reason is allegedly that Activision has noticed the amount of money being made off of purely browser games and MMOs and how things like "City Of Steam" have for their various failings made unprecedented usage of the technologies. Supposedly what they want to do is try and re-launch a version of the "Imagination network" to compete with STEAM and Origin. They basically want to build a browser-based game hub where high end browser titles can be played, which will act as the incentive/anchor to get people to step into their marketplace where they will be selling games, streaming, and other services as opposed to just flat out dropping another "me too" market into the mix. Given the desire to resurrect old name brands and such, allegedly they want to make "Ysebrius" and "The Realm" two of the titles off of this new service, both of which were old MMO-type games you might occasionally hear the truly ancient grognards talking about "Ysebrius" was one of those games people left when they went to things like Ultima Online, Ascheron's Call, or Everquest... and where a lot of the elitist attitudes from those days came from". I believe "The Realm" made some geek-news (very old school version of it) for having the first online wedding between game characters or something like that, and Sierra's magazine covered how there was a player doing wedding services for people almost full time.
That said, as GoG, and the indie-market have shown there are markets for the whole quest/adventure genera of game, with a few games like "Heroine's Quest" being released for free and becoming quite popular in certain circles. It wouldn't surprise me if there will be an attempt to revive the old "quest" franchises, or even if that becomes the point of the entire thing.
Nothing reliable of course, but I actually heard this first as "I heard they are going to bring back the Imagination network if anyone remembers that" which seemed to be jumping to conclusions, and this seems like the same basic information that was based off of. All the specifics were some anonymous dude saying he knew a guy who heard from another guy who works for Blizzard... you know that kind of stuff.
Of course according to that rumor part of the reason this is being done is because Blizzard is taking too long to finish "Project Titan" which was originally going to be a competitor of sorts of "Old Republic Online" then got pushed back, and very little has been said about it since. The lack of any news to begin with, being one of the few reasons why there hasn't been much noise, but supposedly it's turned into a giant development cash pit so Activision is looking for other online games to have out there alongside WoW.
At any rate, I'm not holding my breath for any of this, but it might be interesting to see what a modernized version of Ysebrius working through browsers would look like. The original (which was a companion/sequel to Fates of Twinon) was a sort of cooperative party based dungeon crawl.