This is comparing to the current meta snapshot. I want fast and quick combos and a somewhat consistent turn 9 finish, so a 6mana card that doesn't do anything for about 80% of the game and a 2mana 3/2 that's the same is a no go for me when i want to empty my hand. A 5 mana card with Antique Healbot is a big investment and again, the less clutter the better. The Target Dummy I'm still not sold on but I do see their merit with Valdris Felgorge.
Instead, I run double Doomsayer for more proactive stalling and Loot Hoarder as another card draw option that still works with Plague of Flames. A single Corrupting Mist is squeezed in as a good board clear that can be cheaply discarded for handspace when needed.