I think you're overlooking a bigger conceptual problem with that set. With rolls being a lot stronger, there's now even an inherent danger in even trying to punish them. One of the commentators says it himself in one of the matches, "It funny how M2K tried to read that roll and got punished for it." People still have this conception that every time a player anticipates an option it's a "read" as if the player knew what his opponent was gonna do. In actuality, there are only really reads when the player can pick up on particular habits, and habits are formed when players become accustomed to a set of safe options. But like you said, shielding and spot dodging are at least just as good as rolling, and I think both players are aware of that. When this becomes the scenario, there is no longer a preferable option, and trying to anticipate one is literally a guessing game, and commiting to any of those guesses puts you at risk of being punished.
The particular problem with rolling is about positioning. From a neutral perspective, no player is ever disadvantaged by a roll, unless they have already commited to an option. But mounting an offense requires exactly that. If there was no rolling and only shield and spot dodge, commiting to an option wouldn't be as dangerous because the player on offense has the security of knowing that the opponent cannot change his position on the stage. He could pressure the shield with something as simple as charging a spaced forward smash. Indeed, this would make shielding a terrible option all around. That's why rolls exist in the first place. But, the rolls in this game are so fast and have few vulnerable frames that any option that requires the use of a move that has more frames than the roll (of which there are a lot) is punishable, which makes the theory of even trying to have an offense based on whether or not X character can throw out a move fast enough that a rolling char can't get a guaranteed punish. It's no surprise that Diddy became popular because he's got grab, fsmash, and dsmash which all have good enough frames to reliably punish a roll, but those options aren't available to a lot of other characters.
Of course, a player could always position himself in such a way that he is not close enough t she shield opponent to get grabbed, but still close enough to punish any roll, but this does not give the opponent any incentive to take any action at all. If this were a scenario where the shielding opponent had the percent advantage the smartest thing to do would be to do nothing, because the person at the disadvantage eventually has to make a move. And making a move in this game tends to make you more vulnerable because of how fast rolls are. Indeed, the only way to really change the tides of a battle is to make a hard read or a good guess, but the former requires actually knowing what the opponent will do, which is rare. The latter is more likely the cause of any shifts in momentum.
As it stands, getting "outplayed" either means that you had a definitive grasp of the opponent's strategy (which I would not say is evident in the GF video that was linked), making better guesses about what a player will do in shield, or simply being patient enough to commit to less options thus being punished less by a roll.
tl:dr
Shield, spot dodge, and roll are all incredibly safe options, but roll can most reliably punish a player for trying to have an offense.