Sonic Heroe,s a.k.a Knuckles Chaotix 3D, has Great Writing

Heroes should have been a spin-off game focusing on the Chaotix. If you take as if the other storys weren't there then it satisfies many formal story telling criteria, using this as a template.....

http://www.dailywritingtips.com/how-to-structure-a-story-the-eight-point-arc/

Stasis- They run a dective agency that isn't doing well as their laughably absurd policy is, "We never turn down work."

Trigger- A mysterious package arrives 

The Quest- Anonymous client needs help, the journey begins.

Surprise- Very fittingly for a story about detectives there's a mystery going on that isn't completey obvious from the get go but gives enough clues spaced throughout to make you think, "Oh, I should have seen that coming." The key here is that it doesn't directly tell you any clues right away. It keeps things unobvious. This makes you pay attention closer as it makes your mind desperate for details, so when you do get crucial information for solving the mystery, it really stands out and feels rewarding.

 So, then the story gives you all the clues you need to figure out it's Eggman with the fake Eggman scene, but again the key is vagueness. If the viewer still didn't get it, then in the next scene the person speaking from the walkie talkie says, "What I am the world's greatest.. I mean he is the world's..." This does two things.1.As state give people an additional, and 2. It rewards those who figured out it was Eggman with the assurance that they made the right connection. 

Critical Choice- So now that the Chaotix have deduced they're working for Eggman they have a critical choice to make. Do they press forward and rescue someone they know is and consider evil in pursuit of money, or do they abandon the mission knowing freeing Eggman could ultimately cause havoc. Considering that Vector, the team leader, decides to plow forward, it reveals that he really is greedy and desperate for money.

Climax- The consequence of choosing to proceed is the continued danger they face throughout the rest of the levels, and epic showdown with the Egg Emperor. With Eggman turning out to be a fake again, Vector is sure that he was right, "after all."

Reversal- The player and the chaotix definitively find out if they had the right answer to the mystery as they Find Eggman in a bunker. Now, the consequences of Vectors critical choice bear fruit. He choice to be desperate for money despite knowing he was working for an evil person and it backfires on him. Eggman has squat. Cartoony violence ensues and the screen cuts to black. 

Resolution- Ignoring the actual last story ending here, we can assume that chaotix went back to their detective hut, and hopefully learned their lesson. 

The chaotix definitely have a lot of personality, character, and charm. They use a lot of plausible cultural speech and humor like Vector saying to Rouge, "Who's this broad." (That cracks me up.) The ninja thing with Espio, in the level he says, "Spirit's unite!." That's another thing it does well, makes efficient use of the gameplay time by having the characters talk. It's a great strategy as it give us more details about the story and characters that would otherwise have to be told scarce and expensive cutscenes. Lost World gets +1 for doing this too, except it makes no sense why the Deadly Six are standing around shouting at Sonic the whole level. 

In general, again assuming that Sonic and the cast didn't already have established character traits and backstories, overall the writing for the character and story is all pretty good. Having silly reasons for fighting each other is deliberate so that's not a flaw, it's calculated. The game's TRYING to be funny, and I think a lot of the time it's successful. Just about everything Omega, Vector, or Big says cracks me up and I find "psychopath" Amy funny too as I told you before. Beyond that, probably every character has said something that made me laugh; however, Sometimes it's unintentional, like, me laughing at the idea that Sonic  developed schizophrenia, post trauma stress, or perhaps best of all Megaglomania after SA2; Knuckles warns him of dangers ahead, Sonic says "Yes, we are. We are going out of our way to go into that dangerous place." Or, the infamous line,  "Because we're Sonic Heroes!" Not to mention the fact that he wanted to kill to Shadow now for some reason. Shadow: It'll be a day to DIE for Sonic: "Hey that's my line."

The same writer that wrote SA2 wrote Heroes. It is decent enough. The reason we don't like or approve of it is because it messed up what we loved about SA2 because Sega executives wanted a light hearted game. It's not poorly written, but in fact shows a considerable amount of skill and attention to detail despite being short in comparision to the previous stories. It'd be nice of if it didn't mess up the canon by reseting Shadow, but  other than that and overall it's a funny, light hearted, and well written story.
One more thing, In the last story Metal Sonic is presented as a legitimate threat, and his power isn't arbitrary. To paraphrase  Eggman, "He's copied all of data and combined it with the power of Chaos. He'll be impossible to defeat. It will take a miracle." Then they beat him by, (cue cheesy emphasis) "The power of team work" and the chaos emeralds. It then resolves nicely with the character gags. Again, the fact that everyone is a bit out of character is a deliberate attempt to keep the tone casual, so it's not a flaw.