The topic has merit, but the examples aren’t the best of examples.
Many cards aren’t “strictly” better, but they may well be better because their most common use is just more efficient and specific than previous cards.
Cram Session is just better than Research Project was for Mage combo decks, if you just have some Spell Damage minions.
Overgrowth is more efficient ramp “gain 2 mana crystals” than Nourish.
Breath of Dreams is better Wild Growth in Druid decks with dragons. (And they nerfed the Classic cards so these expansion ramp cards would be appealing for their Mana cost)
Free Admission is almost like Sense Demons, but with a potential upside if you build your deck around Demons only.
Swindle, Secret Passage, Foxy Fraud, draw you cards more efficiently than Elven Minstrel does.
Nitroboost Poison, while it gives a minion and your weapon +2 attack, +1 less than Tinker’s Sharpsword Oil, it costs 3 mana less, and can target a minion, instead of a random friendly one.
The downside of needing to be Corrupt is somewhat negated by being at 1 mana, and Oil needing Combo.
School Spirits does the same 2 damage AOE as Demonwrath, but also shuffles 4 healing in your deck that has synergy. The “upside” of Demonwrath not damaging your own demons can be had by using Firebreather instead, which also gives you a 4/3.
Sword Eater: 3/2 weapon with 2/5 Taunt, vs Arathi Weaponsmith 2/2 weapon with 3/3.
Better weapon, and the 5 health and Taunt is more valuable than just 1 more attack.
And how about all the Rush minions? Lots of value in that. Doctor Krastinov vs Captain Greenskin, Rush is valuable, and Greenskin was played mostly in Rogue and Warrior to begin with, even though other classes could use it too.
Hand of A’dal is practically better than Potion of Heroism, and Flash of Light, especially for those early game stats. There are small cases where the older spells are better, but you want specific situations/decks for that (eg: Heal Paladin)
All the Librams can be cost-reduced, so while Libram of Justice starts off more expensive than Equality, it can become much better, especially since it comes with a 1/4 weapon.
This makes Libram of Wisdom comparable to Sound the Bells. Not strictly better, but since the Libram can be played across multiple turns and allow each minion to be buffed +1/+1 and traded within the same turn, it is more versatile.
It is a little concerning seeing the Forged in the Barrens cards, it signals a new level of synergistic cards allowing to be more broken because they are less general and more specific to a deck type.