In his article about the mini-expansion March of the Machine: The Aftermath , head designer Mark Rosewater notes that there were many impacts from the failed invasion, but the two biggest are that: Most Planeswalkers lost their spark, and There are now Omenpaths allowing non-planeswalkers to travel between planes
Reanimation returns the card to the battlefield, but recursion technically means returning it to your hand (or having the option to cast it again from the graveyard)
+1/+1 counters are small fry for Atraxa
And I guess you can use boast effects twice if you really want to, but the available pool of boast cards is small, underpowered, and sometimes doesnt even get anything of consequence out of a second use
Castle Embereth +1/+0 may not seem like much, but in decks with dozens of creatures like Krenko, Mob Boss, it can functionally double your board's power
As if I need a reason to build another one