Only restricts special summons from extra deck. Which makes it a bad card. If it restricts special summons from hand and graveyard too to a maximum of 3, then it might be unto something.
This card particularly was designed for stopping/crippling pendulum summon.
Which is why it has no impact on the current meta.
The only deck that "possibly" affected by this card is Mayakashi. Even then, Mayakashi could already synchro climb up to level 7 if they start with level 1 non-tuner.
Anonymous
Pinzerprowhat