Let's just say Aia has fast-moving tectonic plates compared to Earth...
Anyway, back to the discussion of AV characters!
I think character development is one problem in Aveyond. Especially in AV3. The characters have personality, but no development. Edward in the end is still the same Edward as in the start. Lydia in the end is still the Lydia in the start. They don't develop throughout the story. None of them do, except maybe a bit of Galahad or the girls falling for Edward. Don't you think after all those events Lydia would act nicer or Stella would be a bit meaner?
It's even worse in AV2. (Note that I've only played build A). Yeah, the characters are cute and all, but they barely have any lines. Character development? What can be developed? They have no character.
AV1 doesn't suffer from this, though. An obvious example being Lars. I also feel that both Rhen and Dameon developing through the game, although it can be just me reading too many fics. None of the optional characters do, though.
Another thing is about the 'tag-along' characters. Aveyond has problems with these. Av3 has partially solved this problem, though...which is ruined by TLO. Let's see their reasons for joining the party:
Rhen : I'm the Chosen One!
Lars : I'm not going to let Rhen steal all the glory! But I got close to her and want to help her.
Elini : I want to find a new hubby so let's travel together because it's safer! And let me tag-along even when I've found him. -> tag-along
Te'ijal : I'm bored and want to go on an adventure -> tag-along
Dameon : I'm going to get close to Rhen and convince her to join the dark side...although I didn't even try
Galahad : A lady must not be in danger! -> tag-along
Pirate John :You need a dragon rider? Let me join until the end and watch me become Elini's slave! -> tag-along
Mad Marge : Hire me! I totally suck in battles, though! -> tag-along
As you can see, almost all AV1 party members are tag-along and have no impact to the story at all besides Rhen, Lars, and Dameon. You only need Pirate John to ride the dragon. Well, you can say Lars is tag-along, too, but at least he had a major role before he joined and have proper interaction and development with Rhen.
Ean : I'm gonna save Iya!
Iya : I'm gonna be saved be Ean!
Rye : I want to go on an adventure! -> tag-along
Nicolas : My big bro told me to. -> tag-along
Gavin : I'm bored -> tag-along
Ava : Dragon Dung ordered me to -> tag-along
Emma : Thanks for letting me enroll to the school even though we barely knows each other -> tag-along
Jack : Thanks for releasing me from the curse -> tag-along
AV2 is even worse, with Ean and Iya being the only person that has any impact in the story. The other characters may as well be mere NPCs and none of the story will change.
Mel : I'm the Darkthrop descendant
Edward : I want to go on an adventure! But I also have a big emotional impact for Mel.
Stella : I lost my memory that might be related to the plot!
Te'ijal : I have to stop my brother!
Galahad : I need to stop my brother-in-law!
Lydia : I'm not gonna let Mel steal Edward! -> tag-along
Ulf : Thanks for letting me out of the prison -> tag-along
Yeah, there's a lot less tag-along characters in AV3 LoT and GoN. Actually, you can say Edward and Galahad are tag-alongs too, but they have pretty major interactions with others so they're not as obvious. Same thing with Lydia, she has proper interactions with other members so she's not that obvious of a tag-along. Ulf is the only obvious one.
Mel : I'm the Darkthrop descendant!
June : I want to get my Magician's Certificate and constantly whine about it! -> tag-along
Edward : Mel, WAIT FOR ME! Crap, my kingdom's been taken over..
Ulf : I just accompany Edward and leave your party for half the game -> tag-along
Yvette : I want fun adventure! -> tag-along
Spook : I'm Gyendal in disguise!
Yep, TLO has taken a step down from GoN in that June and Yvette are obvious tag-alongs. Ulf is also one, again...