Personally, a probability closer to 90% is preferable when winning the game will likely hinge on whether we play a one-drop
At the same time, access to black gives players the option to drain life from their opponents and give it back to themselves, ensuring you stay up on your dwindling opponents
In theory, if a card was banned in that time frame, it's clearly too good for the format because it was competing with all of the super-pushed cards that came out recently and was still deemed bannable
Prowess already sort of lends itself to a tempo-based gameplan, and red removal could be great against the format if it starts out fast to take advantage of the untapped duals and pain everyone is inflicting on themselves
Moreover, it is far from coincidence that even the most recent Pokmon TCG sets must-have cards generally consist of rarer cards, with that higher rarity often being tied to both more impressive artwork and more powerful gameplay potential