edit: How about this; after a move hits x amount of times in a combo, it will whiff until the combo ends. That would end all infinites, not just chaingrabs, and not sacrifice anything but infinites.
Then what counts as a combo becomes the main concern. If it's being in a constant state of hitstun, people will just be able to abuse things like jab -> grab to get around it. If it's time-based, people would just wait longer between throws, etc. Hitstun scaling wouldn't be too difficult to implement, I guess, but, that also suffers from the same problem as defining a combo, and with Smash already having a solid focus on individual hits, it could make balance difficult, as you don't have to worry about any of that if you use a character like, say, Ike.
Infinitely until kill percent against a wall, making all stages with walls insta-banned? This is a good thing?
But how are they good? Why do we need them? How would the game suffer without them? That's what I've been asking, because none of you have even attempted to explain why getting rid of all chaingrabs wouldn't be worth an absolute surefire way of getting rid of infinite chan grabs that's simple and affects nothing else.
I just said they would be okay if grab-release -> re-grab wasn't a possibility, because the potential for an infinite would be overcentralizing when you consider the negligible risk.
That said, in the case of stages with walls AND it not affecting a great deal of the cast (such as the Squirtle air-release -> running grab), I think that's fine, too. Very specific matchup trouble on very specific stages would just be a weakness of a character, like how tethers can't recover well on Port Town Aero Dive. Either way, it's not grounds for auto-ban as long as the stages are designed well (who says you have to be on the ground connected to a wall?) and it doesn't degenerate general gameplay. If every other character functions just fine, and it's just a bad Squirtle level, then he's perfectly capable of banning it, since it just gives Squirtle a weakness to grabs on every other level, which can be considered a balance thing, and not necessarily an issue.
Attempting to change the grab/throw system in a universal way to prevent any possible chaingrabbing would lead to a huge reduction in varied kinds of grabs.
If you prevent throws from ever putting the opponent close enough to grab again while vulnerable, you've eliminated a large portion of the tech chase part of competitive play. Again, very little room for follow-ups.
If you prevent the ability to grab while the opponent is still in hitstun, many short strings such as weak hit -> grab would be greatly limited.
If you prevent the opponent from being grabbed immediately after being thrown or grab-released (on a timer or something), you limit combo opportunities. Saying that U-Throw -> U-Throw shouldn't be a thing is like saying U-Tilt -> U-Tilt shouldn't be a thing.
I imagine the best "fix" would be to give all throws that put the opponent in a grabbable position afterward decent knockback growth, as it prevents chaingrabs from lasting very long. Again, though, giving characters different weights and fall speeds will inevitably make some characters more susceptible than others, though, again, it's just like how Bowser in Brawl or Fox in Melee are easier to combo than most characters.
As far as mindless chaingrabs for long periods of time are concerned, that's REALLY easy to fix. Just make grab-release frame data identical for the whole cast, don't give any characters an air-release animation that ends with the opponent being able to re-grab (at least in place), and don't give characters throws with no knockback growth the ability to chain into themselves. Universal fixes that take minimal effort and fix any reasonable problem associated with chaingrabbing. Brawl was just not designed with those basic concepts in mind.
