I've stopped seeing "Premium Class waitlist" on most of my reservations, but that's fine with me. The automatic system for upgrading passengers to PC never seemed to work well for me, so I'd gotten in the habit of manually selecting a seat in PC when the "upgrade window" opens. Even if your reservation doesn't say "Premium Class waitlisted," your status still lets you select a PC seat for free (via the "change seats" flow) during this window.