Shadow is unironically better than Heroes. The controls/physics are tightened up a little, and while it can get annoying to Westopolis at the start of a playthrough every time it's overall not as repetitive as playing through every team in Heroes. People complain about the missions, but most can be done quickly and smoothly, in fact you're supposed to to get an A rank; there's only like 2 or 3 missions that are straight up bad. And it's not like Heroes didn't have some annoying missions when playing as Team Chaotix.
I respect your opinion but for me personally I still think Heroes even with it's flaws is more enjoyable than Shadow's spinoff game.
Sure, Shadow doesn't have as much repetition in terms of dragging out a whole playthrough with minimal changes to stage length and obstacles/enemy placement except for Team Chaotix's missions, but at least Sonic Heroes still at it's core felt like a Sonic game and it's fun tearing through robots especially after getting a couple of power cores. (The big helmet robots without team blast to demolish them are a big pacebreaker though)
Shadow with it's base gunplay structure does play decently enough since the auto-aim for most weapons works decently and you mow through most enemies with ammo to spare, but the mission structure can at points be worse than Team Chaotix's just in how long it can take or easy it is to get lost. (Mad Matrix's bomb detonation, Lost Impact's Artificial Chaos hunting and The Doom's level layout come to mind for major examples)
Shadow also suffers from a poorly implemented 'choose your own adventure'-type story structure in where while the 3-faction war is somewhat accounted for, the characters are written without any real continuity for the loose events in the game in mind, a major example being the afore-mentioned 'Shadow realizing he's an android from Space Gadget or Air Fleet'-cutscene leading up to Lava Shelter, but another example for me being how Black Doom and Eggman oppose Shadow with boss fights even if you did their side-alligned mission but readily request his help in the next potential stage like nothing happened.
Hell, Shadow Generations didn't even include one stage from his own spinoff game yet are fine with pulling a stage from Frontiers, a game he had no presence in whatsoever.
I like metal being able to talk and don't like the "completely mute" metal of the post heroes sonic games. Heroes while his only first real 3d appearance shows he can talk in both base form and neo metal form
Do you mean like with the dialogue prompts in Sonic Generations for example? I don't recall Metal Sonic actually talking in the games in his base form myself, but I would likewise appreciate that upgrade being retained to give him more character besides just being a silent enforcer/boss fight-trope character.
It's sad because Metal Sonic has all the groundwork for being a really interesting character. It just so rarely gets taken advantage of. A robot that's hard-wired to always think that he's the real Sonic and that the actual Sonic is a copy is interesting...but it rarely ever goes anywhere.
I always imagined it being the result of so many defeats taking it's toll on his memory functions to the point he's deluded himself into thinking like that, really showed how Metal Sonic's at his breaking point that he's willing to usurp his creator and go through such lengths just to satisfy his own pride.
And after that and Free Riders also having him backstab Eggman for another rematch with Sonic, he goes back to being boss fight fodder. Kind of a shame really as likewise I'd appreciate it more if Metal Sonic would have more character to him and reclaim his spot from Shadow as Sonic's rival.