>>40100383All the Team Flare stuff is pretty heavily rewritten to feel more like what a potential Pokemon Z would've had (they're after Zygarde, not Xerenas or Yveltal). Tierno and friends have very different roles and don't appear all that often. There's a contest-inspired subquest Serena works on while Ash challenges gyms. Sina and Dexio are replaced with two cute girls.
That's basically it for the "plot" stuff it has in common with the games. The Pokemon anime is primarily about following a group ofcharacters on a journey, not watching an exciting plot unfold. Episodes are primarily character-centric, not plot-centric.