Gotta say that i haven't stepped into these threads in forever, and i have yet to really touch a kh game in years, so i'm a bit rusty on a lot of this stuff.
Anyway, i have to say that Kingdom Hearts for me at it's beginning was definitely the game to enjoy, and like many older members here, it was the prime of any of its future titles. I didn't care about the basics as it was just a fun story for me. Had it restrained itself from being complicated, then yeah maybe the series would have seemed bland, but at the same time, it's really how they go about it that takes the toll.
I've played games that progress itself to its players as to giving itself an edge, but KH adds stuff to tie loose ends while creating more stuff that completely bloats the series into a muck of complete wtf. They've created characters to give other characters a push into fleshing out their characters, and then they throw them away, and if they re-use them...well how interesting are they the second time if they were so forgettable then?
KH is not a hard story to understand, but it has it's fill of useless complications in my opinion. Albeit the situation with Xehanort is becoming clearer after DDD, but it's funny how everything up to that point felt like filler. Often times i felt like i wasn't playing Kingdom Hearts anymore. I feel like this series is riddled with trying to make itself look cool on top of it's story, if that's what growing up with a series means.... I played Kingdom Hearts 1 when i was 13, and i'm getting close to my mid 20's and in no way has my view of gaming changed. I know in myself what game feels good as opposed to feeling a little off, and i understand everything is opinionated, so don't all radical naysayers of OP's thread get their panties in a bunch, but too much is too much, y'know?
I think Kingdom Hearts is capable of being a good game by just making a simplified transition to being a little darker, with few complicated stories just to add twists. Most games do that anyway, but i think Kingdom Hearts...didn't know what it really wanted to do, so the story added more than it really needed. It's a bit laughable sometimes...but again, just my opinion