I actually like 5e at tier 4 play. You kids have no idea how good you have it. We had to play up hill, both ways, in the snow and we liked it because we didn't know any better.
I ran ad&d 2e up to 20ish (class-specific xp charts, yay) and 3e up to 23rd. 2e was a slog imo, with casters totally dominating. 3e let you use PrCs to balance classes more and Bo9S provided a nice burst of spice to high level melees, but it was still very caster heavy.
5e did a lot to slow down casters. People talk about how powerful 5e casters are but earlier edition casters were soooo much more powerful. I had to deal with casters who had multiple Miracle or Limited Wish spells prepared. (Limited Wish in 3e was called "instant scribe scroll" by our group)
A 20th level 3e caster had 4-6x 9th level spells/day, and similar 6th, 7th and 8th. In 2e, a mage got 2x 9th and up to 4x 6th level. Meanwhile 5e characters get ONE of each 8th and 9th spell slots and no more than 2x 6th & 7th.
And yes, 5e casters don't have to pick spells for their slots, but neither did 3e sorcerers. And they knew far more spells than 5e casters. A 20th level 3e sorcerer knew 34 spells (5x 1-2nd, 4x 3rd-5th, 3x 6th-9th). 5e casters top out at 25, sorcerers stop at 15.
A 3e sorcerer knew twice as many spells as their 5e counterpart, had more than twice as many spell slots and the spells hit harder. Let us not forget that in prior editions, spells auto-scaled. 10th+ level caster always threw a 10d6 fireball using a 3rd level slot. A sorcerer 10+ could throw a half dozen 10d6 3rd level fireballs. (I'm going to assume the hitpoint inflation of 5e is offset by changes in saving throws, but I haven't done the math)
Concentration was also not a thing: if the spell got cast, it functioned for the full duration and the caster could fire off a second spell. Or a third. Or a fourth.
So in summary 5e does tier 4 casters better.