There is no such thing as Grass/Lighsworn/Neos/Invoker engine. People are abusing these cards in almost every single deck. All those cards deserved a nerf.
Good that Konami made that clear this time. Grass should not exist, Lightsworn engine is ONLY for Lightsworn. They can always allow Charge of the Light Brigade to be at 3, but you cannot use this deck unless you have 6 Lightsworn monsters with different names in your deck.
At this point I believe konami has no damn idea of what they add to the game, like neos fusion I can assure that in the whole world only konami thought it wouldn't be used outside neo spacial decks. Same with lightsworn
"Lightsworn engine is ONLY for Lightsworn."
Except pure Lightsworn got hit harder than any of the decks utilizing the engine. Now they can't use kiteroid or any limit 2 cards.
Yup blair should have a skill that adds a another copy of Brigade to her deck if she have 6 or more different Lightsworn monster in her deck or something.
This way, pure Lightsworn deck would be able to use 3 Brigade instead of just 2 because of the banlist.