Incenjucar
Legend
In 4th edition, spells don't scale by level or have silly and arbitrary HD limits. Sleep is just as useful at level 30 as it is at level 1. While this was a very nice change, 4e still had the problem of spells becoming obsolete, it just did it in a different way. In that edition, you replaced old spells as you gained higher level ones. They literally disappeared from a wizard's spellbook, even! This makes me roll my eyes every time I read it.
In 5e, can we not have any form of spells becoming obsolete at higher levels, pretty please? This goes for fighter "exploits" too. The idea of a fighter suddenly forgetting how to cleave once he learns whirlwind attack is just as stupid as spells disappearing from a spellbook.
The few scaling powers in 4E is certainly a problem, not so much because of the "forgetting" issue but because of the inability to get better at something. However, there are a number of powers that DO have scaled versions later on in the game (though you usually have to track them down), and the skald bard (FINALLY) introduced Lesser and Greater versions of powers to the game, though this should have been in on Day 1.