Janna - purely shields, decent CC
Lulu - purely shields, movement speed
Taric - heal shield
Yuumi - better heals than other supports, better movement speed, better ultimate, better poke, PASSIVE based shield at no cost (gives mana)
So a Yuumi playing into a Janna could literally just sit in lane afk, pressing W every now and then and his laner wins by default because the enemy team HAS to recall first?