Wiegraf, since there's no accounting for taste (I love X and think it's the best in the series; some days it's my favorite, some days VIII is), I'm not going to comment on most of the things you said involving favor or disfavor, but there are a few things I feel a need to point out.
Tidus was an annoying, selfish, whiny, brat who didn't know how to grow up.
Mira already pointed this out, but selfish is so absolutely an inaccurate adjective to describe Tidus. He was very kindhearted, rushing into the temple at Besaid to help a summoner he didn't know (he also thought it was some old dude, not a cute, young chick) and saying "It's the right thing to do" to take out the Chocobo Eater when he heard about it.
Then, of course, there's sacrificing himself.
He didn't whine much either, and when he did, it was always justified. Losing your home, your comfortable life, being stranded in an unfamiliar world, becoming dependent on the kindness of others, finding out that a chick you've fallen for is going to die, etc. are all legitimate things to get upset about.
And, yeah, he grew up big time.
Wiegraf said:
Kimahri was a useless filler character who could have been removed. As could Lulu. Yes, they had a bit of importance, but nothing that couldn't be rewritten to not include them. It AMAZES me that people complain about FFXII's Penelo and Fran when they had just as much importance as Kimahri and Lulu. Even Rikku wasn't important and was just going along with them due to the fact that she was Yuna's cousin (hated this story element).
How many characters in any FF are as vital to the plot as Cecil, Kain, Terra, Celes, Cloud, Tifa, Aerith, Squall, Zidane, Tidus, Yuna, etc.? That's kind of a weak complaint. You could insert just about any supporting cast into these games when the main story doesn't hinge upon their personal stories.
Wiegraf said:
Okay so what is the point of being sent? Yes, it can turn you into a fiend, but Seymour, Yunalesca, and Auron all proved that it can effectively make you exist forever. So dying can actually make you live permanently.
Most people can't become unsent like that. It takes a strong will. The average person just ends up becoming a fiend if they aren't sent.
Wiegraf said:
Sin was CONSTANTLY used as a plot device to take the party somewhere (like when they were underwater and then Sin suddenly appeared and decided to take them to a desert) for no real reason at all (intro excluded because he admittedly did have a reason).
So he was used to do it twice, and once because it was an explained, deliberate action on Jecht's part. I'll grant you that the Macalania-to-Bikanel journey was catering to the plot's need to get the group to the island, but it wasn't any more egregious than most such things in other FFs, or RPGs in general.
Wiegraf said:
"I think they expect us to just give up and die down here"
xD ARE YOU SERIOUS? So, the main villains thought that the best plan to kill these people who have repeatedly killed everything that got in their way was to throw them into a pool? Might I remind you that 3 of these people are trained Blitzball players who can hold their breathe for absurd amounts of time?
Yeah, that was extremely retarded on their part. No disagreement there. More catering to the needs of the plot, and a tad more egregious than is often the case.
When my fiancee and I recently played through FFX together (it was her first FF), she asked me at this part "Why don't they just shoot them?" The best answer I could wank out from an in-universe perspective is that they may have done it to give the whole trial-of-heretics-to-execution thing some appearance of legitimacy.
The whole situation involved upholding traditions after all, and executing people in the Via Purifico has been the order of business for handling heretics. That's the best answer I could come up with anyway.
So, of course, she then asked why the threw the ones who are good swimmers in the watery part. =P
The real answer, of course, is for the sake of the plot. This is going to understandably bother some people more than others, but I find it forgivable.
Wiegraf said:
And also, Rikku. Rikku appears after admittedly trying to ya know, kill or kidnap Yuna (reasons aside) and Tidus and the gang just... don't care enough to ask why? No, lets just take her with us. Yep good plan.
They talk to her about it off-screen. Of course they asked why. And it was Yuna's choice who became her guardian, so, this being her cousin, she picked her. Not a big deal.
Wiegraf said:
Even the enemies weren't a saving grace in terms of design. Every other enemy in the game was just a palette swap of a previous enemy. It's like, okay game, give me something new.
That's also true of Tactics, though, and you love that game.
I also find it strange that you dislike the overall gameplay of X since it plays a lot like Tactics, but without the moving around during battles bit. Granted, you also can't change job classes, but each character definitely fulfills a job class-like role for most of the game.