I believe this has been touched upon in other threads, but I haven’t seen it talked about directly.
I played this game for a time at launch, stopped, and then came back at Eldritch Moon, and I have to say one thing in particular stands out to me that changed over that time, and that is how one deals with enemy creatures.
During the Origins set for direct removal (not counting damage to creatures or sweeper spells) you had:
Reave Soul, 3 mana: destroy a creature with power 3 or less
Swift Reckoning, 6 mana: destroy target disabled creature
Celestial Flare, 6 mana: target creature with defender your opponent controls is destroyed
Unholy Hunger, 8 mana: destroy target creature
Cruel Revival, 8 mana: destroy target non-zombie creature and the last zombie you controlled that was destroyed is returned to your hand (did not work if you didn’t have a zombie in your graveyard)
Turn to Frog, 9 mana: target creature is destroyed and is replaced by a 1/1 blue frog creature
While spell removal existed, you more often relied on berserker, defender, and reach to deal with troublesome creatures, but now, coming back to the game one thing that still stands out to me is that Unholy Hunger costs 8 mana to destroy a creature at a time when planeswalkers could get, at most, 6 mana from a single match, meaning you’d have to landfall or cascade in order to destroy any creature the turn after it came out, however, come Zendikar and later the cost for kill spells was dropped to 5 and the amount of mana you could get from a single match went up to 8, meaning now many planeswalkers could cast any removal spell the turn after a troublesome creature came out. The worst offender now being Imprisoned in the Moon at a measly 3 mana, compared to Turn to Frog which cost 9 for an arguably worse effect.
Also consider that many of these kill spells were highly specific, the creature had to have defender, it couldn’t have too much power, it had to be disabled, you had to have a zombie in your graveyard, and you can see how the addition of spells like Grip of Desolation and To the Slaughter have warped the format. While an unpopular suggestion, I would think a massive overhaul of things is needed. Make removal spells cost more. 8 or 9 mana verses 5 seems fair, and make creatures smaller again to make red removal spells like Lava Axe relevant again. Having creatures come out at 11 toughness in the case of Olivia or 16 toughness in the case of the upcoming Heart of Kiran has made red burn spells too inefficient to be manageable in the current environment.