Playing a 5e Class Backwards

What if you played 5e, but at level 1, you got the features your class would normally get at level 20. See, the class features of tier 4 aren’t so much stronger than tier 1 class features, but they almost never see play because very few groups play levels 13 and above.

In some cases, the very identity of a class change, whereas for others, things may not be very different at all.