Yeah and let's just take a closer look at one of the examples - Heightened Metamagic.
- It costs a Metamagic option
- It costs 3 Sorcery Points
- The points must be spent before the enemy creature makes the Saving Throw
- It only works on spells you cast
- It only works on the initial Saving Throw of a spell
- It doesn't also give the PC or ally advantage on one of their own Saving Throws
Now let's take a look at the Psionic Sorcerer. They can spend 1 Sorcery Point and a Reaction to cast Silvery Barbs. It costs 1/3 as many resources as Heightened Spell and is far stronger.
True, Silvery Barbs has advantages over Heightened. That's because it's a different feature, and different features aren't going to function identically. You guys keep focusing only on the portions of Silvery Barbs that are better, not on the ones that are worse.
I'll grant Heightened has all of those disadvantages, and Silvery Barbs has other advantages you missed (it can boost initiative, negate crits, great stuff). But Heightened Spell is only one feature I mentioned. That said, it has some major benefits. It's action cost free. It costs a resource, but is only very slightly more expensive than Silvery Barbs when used normally (with a spell slot). Reactions aren't free. Reactions are an important part of your action economy, especially as a full caster.
For an even less favorable comparison, compare Silvery Barbs to Hound of Ill Omen. Hound of Ill Omen can make not one saving throw be at disadvantage, but can make fifty of them at disadvantage! Let me hasten to point out, because I suspect you'll miss the point, obviously no one is ever getting full use out of Hound of Ill Omen like that. It can be knocked down. It has to be next to a target. There are disadvantages and it isn't going to be useful in every fight. In that same way not every fight, or every session, is going to have one key roll you'll even WANT to spend a reaction and spell slot on rerolling. And when you do have a key roll line up and use Silvery Barbs? It's just another roll, it isn't always going to go your way. And then you've used your reaction. No more Shield (which I maintain is a dramatically better use of a reaction), no Counterspell (higher level slot, same reaction cost, also a way better use when it comes up), no Absorb Elements (another fantastic reaction that, when relevant, blows Silvery Barbs away in usefulness), and you might not even get the result you want!
This is the spell you are calling to be banned? This is the spell that you say is worth using in a fourth level slot? It only competes effectively with the competition for spell slots and reactions because it's versatile. It's good, it's worth taking for a wizard or bard (though probably not a sorcerer), but it's just one reroll at the cost of your reaction and a spell slot! One reroll! I'm genuinely floored. How many creatures do you typically face that one reroll is that big a deal?
"But it also gives advantage to an ally!" Advantage is something you also wildly overblew in importance (going so far as to smugly assert my downplaying its relevance means I don't know what I'm talking about). Want advantage? Get a familiar. In fact, everyone in the party, get a familiar. Better yet, cast a spell that impacts an area, so you can grant your entire team advantage on more than one swing, on more than one target. Advantage on one attack?
One?