Flow\Parsoid\Utils::htmlToPlaintext does what Sanitizer::stripAllTags already does & we should probably re-use that instead of inventing the wheel.
Flow\Parsoid\Utils::htmlToPlaintext also truncates. We can either keep htmlToPlaintext around & make it call Sanitizer::stripAllTags (instead of stripping ourselves) & Language::truncate, or get rid of htmlToPlaintext altogether & call both of those wherever we're currently calling htmlToPlaintext