Mangara, the Diplomat
Oracle Text
Lifelink
Whenever an opponent attacks with creatures, if two or more of those creatures are attacking you and/or planeswalkers you control, draw a card.
Whenever an opponent casts their second spell this turn, draw a card.
While this card isn't Smothering Tithe/Rhystic Study (harder to activate, easier for opponents to avoid), I still think that it would have an impact in quite a few games... at least on a casual level.
Tax/restriction effects are hard to design as they tend only to be playable when they are so taxing/restriction to be unfun like counterbalance.
That said the idea behind this design is great, adding a tax effect onto a creature or something else of value can avoid this design problem. Ie you can make a weak tax effect playable by tacking it onto a good enough creature like eidolon of the great revel.
In this case the creature is far too weak I'd say though. This should have been 3 mana i think as the tax effect hits very few decks anyway.
The best design for a tax effect imo is some artifact/ enchantment with an ETB value effect and then a little tax effect staying on the board. Provides your opponent with interesting decisions if they should remove it or not.