In EW 2007 there was a Powerpoint icon in the schedule chooser to import a Powerpoint presentation into the schedule.. You now have to go into "Add Item" "Browse for Powerpoint File" to do this. We used the 2007 Powerpoint Icon to quickly add a one off Powerpoint to the schedule (e.g. Weekly Notices and one-off sermon presentation) which does not need to be kept from week to week in the "Presentations" list.

Have you tried dragging the powerpoints into the schedule? You can select all the powerpoints at one time and drag them in. 

Dragging and dropping appears to work pretty good but then you have to order them correctly.  Since there are no longer icons for moving the items up or down this take a bit of extra effort.  Dragging and dropping within the schedule to change the order is hard to do with the items expanding while you are trying to drag and drop.