>>718281885
It's not just that. Oko is a phenomenally broken card, it's actually quite impressive how busted they made him. 
Oko is basically a masterclass in overpowered design. All he's missing is drawing cards.
First off he is very aggressively costed, three mono for a planeswalker was very aggressive at that point.
His first ability can gain you life, and create an artifact. It's also a +2 which is a huge contributing factor to why he's so difficult to get rid of. On paper this is his weakest ability, in practice it is one of his most versatile. But still admittedly probably the worst of the three abilities.
His second ability also adds loyalty, for some reason, which is another contributing factor to why he's so difficult to kill. And it functions as: removal, aggro, and blockers! This ability is basically the reason he's so fucking broken because he can, without his ultimate which is its own can of worms:
1. Stabilize you
2. Stabilize the board
3. Create a presence capable of both defending, and pushing damage... Forever.
4. Deal with anything that could threaten him
Then you get the cherry on top.
His last ability trades a food token, which you make off his first ability, for anything that your opponent has. And you can use it typically the turn after you play him, assuming that they can't get a single hit in on him. Which is a much more common scenario than you would expect.
So on top of all that other shit he can do, you also can't easily play threats into him because he'll just trade a fucking food for it.