Both halves of the card are fine but they complement each other perfectly resulting in an overall gem that is desired across the board
Whats going to happen next
1 Aragorn, King of Gondor
Create a 2/2 green Bird creature token with "Whenever a land you control enters, this token gets +1/+0 until end of turn." Flashback (You may cast this card from your graveyard for its flashback cost
8 Split Up A New Spin On The Sweepers Of Old Four mana is where sweepers tend to be costed - anything less would be obscene and anything more tends to be a little slow (though in the latter case, with the right additional effects, it can still work)
In the case of the former, its because the best choices vary not only by color identity, but often by specific deck building limitations: Seismic Assault and many other red effects want you to play an extra-high land count, while a black deck with reanimation and Tortured Existence obviously cares about discarding creatures