Yes, normally you can count on at least 2 of the 3 promoted teams to struggle, but all three this year look organised and very well managed. It's not inconceivable for all three to survive. Burnley and Watford look better than they were last year, Leicester have too much quality, and WBA have Pulis who never gets relegated. Everton have had a bastard fixture list to start, and probably won't be in any danger (with or without RK!). And unlike the shambles when under Saggy, we're probably too good defensively to get sucked in.
So if the above do survive, the ones left are Swansea, West Ham, Stoke, Bournemouth and Palace. Not particularly good teams, but not appalling either (except maybe Palace). Only Palace look like a team who could be miles adrift by the end of the season, but even they managed to beat last year's champions. I reckon Palace and Swansea will go down, but I think it'll be a dogfight to avoid the 3rd spot.