Some the reason why is that the enemies we fight the most frequently now in the early levels have good reflex saves. This is likely not true for the rest of the game.
However in 5e I in general feel that saving throws against spells are too easy. It’s already a limited resource and the spells don’t disable for long or do too much damage. But this is a 5e comment more than anything else.
Good DEX saves and stupid high HP because apparently players hate missing attacks so much HP had to be adjusted. So instead of having 7 HP like in the tabletop, Goblins have 20+.
