You can still adjust the volume of posts from people in your circles, and adjust how much of each you see.
From your home stream, select one of the circles shown on the top, or use the "More" item to pick a different circle:
Once you've selected a circle, you can click on the gear icon that will be in a box towards the right.
From here, you can check the box to say if you want it in the Home stream at all and, if you do, how much (roughly) you want to see. You can also use the Bell icon next to the gear to indicate if you want to receive notifications for posts in the circle.