Having been subjected to every Microsoft chat application since 2000, I can assure you that each one started worse than AIM and got progressively worse.
The only exception was driven by my employer, who opted to embed Cisco Call Manager crap into Microsoft OCS (the circa 2010 chat client). I would rather communicate via requisition notes in peoplesoft than use that shit. Whatever replaced it (iirc Lync for Enterprise Business Extreme Edition) was better.