Effects of Obamacare Repeal

The CBO is out with estimates of what repeal of the ACA will mean in the real world.  Again, why hurry to take all this away without first figuring out what will replace it?  Why take it away at all?  But especially, why throw 18 or 27 or 32 million Americans out into the cold with only the vague promise of “something better” to be figured out later?  And costs?  Please.