What I really don't want is a situation where D&D spellcasters turn into DOS spellcasters where everything looks overpowered but feels underpowered. Spamming weak magic on cooldowns. D&D casters need to be able to peak when the situation requires it, and play smart rather than with reckless abandon.
That is how magic will probably gonna be.
Also, every spell which a player can cast, an NPC can cast. And fighting an enemy caster able to cast tier 7 magic while you can only cast tier 5 is a nightmare on TT games. This spells would't be "pc only" spells. In fact, is common on games with tiered magicl progression to fight enemies with powerful spells before you can learn this spells.
I like what 5e did to save or die spells. While those spells still hit really hard and likely will one hit you if you fail the save (which is more likely with the bounded accuracy approach), there is at least some chance to not get utterly disintegrated and having to reload.
Still hit really hard? Are you joking? Pick disintegrate for eg. A lv 20 barbarian with 20 con with average rolls and +5 con mod would have 19 * ( 7 + 5) + 12 + 5 hp or 245 HP. The average damage of disintegrate is 75 damage(10d6 + 40), which means that a barbarian on 5e can survive failing 3 saves and being disintegrated 3 times.
Pathfinder 1e modified spells like finger of death to deal massive damage. At lv 20, it can dish 200 damage. And Disintegrate can dish 40d6 damage. Or 140 damage on average.
