The east seems like it's relegated to either Boston or the Bucks. I really can't see anyone else truly challenging. Sixers are interesting because embid can straight dominate but injuries.
I still would not count out the Heat. They've been the dark horse and they've eliminated those three teams on a number of occasions now.
Sure, the Celtics and Bucks literally dominate the regular season. However, I agree with you that we shouldn't dismiss the Heat and other Eastern Conference teams. It's worth keeping in mind that great results in the regular season don't guarantee any success in the playoffs. So even teams like the Cavs and Magic could surprise us in the playoffs.