Why was SchemaDirectiveVisitor removed?

[intellix]

I'm migrating to the latest set of graphql-tools packages and one thing I'm having to do is refactor the directives since I see that SchemaDirectiveVisitor was removed.

I've got a directive like so:

directive @sanitize(fuzzy: Boolean = false, minLength: Int = 2, maxLength: Int = 100) on ARGUMENT_DEFINITION

type Query {
  assets(fileName: String @sanitize(fuzzy: true, maxLength: 150)): AssetConnection
}

export class SanitizeDirective extends SchemaDirectiveVisitor {
  visitArgumentDefinition(argument: GraphQLArgument, details): void | GraphQLArgument {
    const directive = argument.astNode.directives.find(d => d.name.value === 'sanitize');

    if (!directive) {
      return;
    }

    const argumentName = argument.name;
    const { resolve = defaultFieldResolver } = details.field;

    details.field.resolve = (source: unknown, args: unknown, context: Context, info: any) => {
      let argumentValue = args[argumentName];

      if (!argumentValue) {
        return Reflect.apply(resolve, this, [source, args, context, info]);
      }

      if (typeof argumentValue === 'string') {
        argumentValue = applySanitization(argumentValue, argumentName, args);
      }

      args[argumentName] = argumentValue;
      return Reflect.apply(resolve, this, [source, args, context, info]);
    };
  }
}

And when I look at the examples here for modifying inputs: https://the-guild.dev/graphql/tools/docs/schema-directives#enforcing-value-restrictions I can't help but notice that it's A LOT more code and complexity. It seems now I have to create a type per usage and cache them etc like:

StringFuzzyBetween2And50
StringFuzzyBetween2And100
StringNotFuzzyBetween2And50

It seems the ability to alter/validate inputs/arguments on use has been completely removed and it's impossible outside of creating a custom scalar. There's no alternative in the examples apart from transforming a schema to use custom scalars.

Obviously it was done for a reason... but I'm searching the net and can't find a single reference to the reasoning behind why SchemaDirectiveVisitor was removed and how to achieve the same thing. What problem did this solve?