If you guys could change ONE(and only One)thing about the entire series, what would it be?

For me..it's definitely the pacing cause it's like a domino affect. You fix the pacing to be more slowed down or at least not at such a insane and I mean insane breakneck speed, you can get a lot more done. We would have way more time for downtime and character interactions and especially more time for characters to be fleshed out and have more moments, you get more time for overall Worldbuilding, etc.

It doesn't fix everything but fixing the pacing alone would've fixed(or at least opened up the pathway for it).

Making the story longer as well would also help.