Mid-game card, not late game. Mid game, and i think its rather fine. And you do want three, because you must think about this mathematically. You don't need to draw it in the early game, but you do need it in the mid-game. And three cards is the ideal number for drawing at least one by the mid-game.
The standard trifecta to any strategy game is
Rush, boom, turtle.
Rush is an attack in the early game.
Boom is a mid-game assault.
Turtle is a late game assault.
Although people usually assume this is a counter system, there is no reason for it to be. Chess for example.
This is a mid-game assault.
Take the Steam Engine/Chimera strategy. You start your early game placing down one steam machine, making use of ice shield for a defense. Build it up until you can afford the chimera, as soon as you can, use the chimera keeping their high attack power. Play another engine, gravity pull it. If possible play a third and build it up.
The high HP of the steam machines make them ideal.
Without the gravity pull, it would be quite overpowered. If you feel it is up, give it a ten hp boost.