It doesn't have as much action, but it has more game
Because one is better as a gorey, explosive, slice-and-dice single player game and the other is a class based competitive multiplayer game
And because it's competitive multiplayer, Overwatch was probably deemed better because of the replayability
Doom's multiplayer isn't quite as good, which is why there's hardly any talk of the new Doom game, but there's almost day-to-day talk about Overwatch