absolute homogeny of the classes and abilities.

I dunno. I played a lot of 2e and so, SO many fights at levels below ~12 played out exactly the same round after round, fight after fight.

Your lvl 20 wizard was a god, but your level 6 wizard could cast like 4-6 combat spells per day and spent the rest of the time as far back as possible using a sling for 1d4/round forever. Maybe an enemy would get too close and you'd hit it with your staff for 1d4/round instead. If your DM ran more than one combat per long rest, this was your life. The ranger next to you was doing the exact same thing but with better numbers.

Your fighter got to swing his weapon for the same damage in the same way each round and that was it. Upon gaining enough experience, he'd graduate to more interesting things: namely doing it TWICE per round instead! Yeah the number on the dice was bigger than the wizard's, but "variety" isn't how I'd describe how it felt to play. And unlike the wizard this didn't get much better at higher levels.

4e had so much going for it on a tactical level compared to that. Every single round you were making choices regardless of class. Maybe you can strategically move enemies around with your attacks. Maybe you apply situational buffs and debuffs. Your friend might be able to force advantageous targeting. You all decide whether to use your action points to press an advantage or save them as an emergency ripcord.

Yeah the numbers were often in the same range as your compatriots', but that's hardly the only measure of variety.