If you gain an amount of life "for each" of something or "equal to the number" of something, that life is gained as one event and Leyline of Hope's second ability applies only once
Most importantly, neither can your opponents if you exile their creatures, making this a fantastic white finisher or protection spell, depending on your circumstances #22
Hydroid Krasis This giant jellyfish has plenty of good qualities
Not only do these decks not need extra assistance closing out the game once they've got a bunch of dragons on field, their players - presumably 'Timmy' types who like big stompy creatures - would probably rather win by smashing face
If you want actual playable Giants, you have Curious Colossus which does a someway decent Humility impression, but then beyond that you just have two forgettable commons
When a player gains one or more life, they take a drink