You can still zoom like the old way. Alt+right used to be a substitute for using the middle mouse button (MMB). But now pressing Alt temporarily switches into Arc-Rotate while you're pressing the key. This make it easier to do a quick pan, zoom, rotate, etc. but it means that Alt+right can't be used as a MMB substitute.
Note: you can now zoom the view with the mouse scroll wheel. If you hold the Shift key down it zooms at the center of the screen, otherwise it zooms around the cursor.