If you want a seat front and center, you still need to arrive early. Seats are still first-come, first-served.
But before FP+, you'd often have to be in the queue 60-90 minutes before the show just to guarantee ANY seat. That's no longer the case. If you aren't picky about your seating location, with FP+ you can arrive 15 minutes before the show and still be guaranteed to get in.