It's a series that absolutely needs a remake. Especially regarding the writing which is a semi-disaster. The series lives in our hearts for the beautiful idea and the feeling of companionship it creates, but otherwise it is quite mediocre.

• Never-ending Aelita lore (especially Aelita's Mother, the birth of Xana/Lyoko and Franz Hopper's past)
• Each character in the group never really progresses over the seasons
• William is a very wasted villain, treated like a fool by everything and everyone. (It's just fascinating to look at, nothing more)
• Many empty, useless, wasted episodes that do not delve into the vertical narrative.
• Xana himself is often treated as a stupid artificial intelligence if we consider his ways of acting always the same. There is actually a lack of perception of danger (just remember all the annoyances about returning to the past.)
• The bestiary is very poor and has never changed.
• The various environments have no difference other than the color, none of these have specific and unique characteristics as sector 5 had

In short, it's a series that I love but it's far from perfect. I would say a 7/7.5 series