The Problem is that Level 5 is probably the biggest Power Increase from One Level to another in the entire Progress Systhem. Even Level 20 Capstones wont match the Power Surge all classes get at Level 5.
1) All Martial Classes get Multiattack.This allows you to deal Double Damage. Thats alone already really strong because what was previously a Tough Fight now can be turned into Cake Walk.
For some Spells its even more extreme.
Imagine a Horde of 30 Zombies against your 4 Men Party. No matter what Gear you have at Level 4 you will get swarmed and die.
At Level 5 every Cleric, or Spellcaster with Fireball can SOLO this encounter. Going from: OMG, we all gonna die, to alright gimme 2 Turns to blast them is a very, very big difference.
Also some "Mechanics" are not applied to the Group anymore. For Example the Hag Boss Fight. Its all about her Creating Dublicates and turning Invisible and running away.
At Level 5 your gain "Counterspell" This completly Stops the Fight, since the Hag cant do anything
Its also the Point where some "Early Campaigns" end. (Lost Mines of Phandelver, Dragons of Icespire Peak)
So jeah i am pretty sure we wont see a Level increase for at least a couple Months.
Its already hard enough to plan for this as a DM, but for Balancing in a Game, where some People hit Level 5 at Different Spots? Oh boy.