Given the Onslaught and Legions sets so far, you're looking at the most powerful creature in the block
That means healing is best used after youve made a challenge, on the same turn
Hogaak became a mainstay for graveyard-based decks from Modern (before getting banned, of course) down to Vintage, where it could be paired with even more busted cards like Bazaar of Baghdad
To go back to Fenrir for a second, lets evaluate the card in terms of card economy: Fenrir replaces itself on ETB with a land, putting you at card parity
1 Counter Blitz Tidus And The Guardians Counter Blitz was released alongside three other Commander decks, each based on a different Final Fantasy game
This ability can also be used reactively versus opposing combo decks like Storm, hence why its a staple of cEDH