But in control and tempo builds, you can play Dragonlord's Prerogative on an opponent’s end step. This is much like the role Jace’s Ingenuity has played in the past. So the potential added protection against counter-magic is useful. But is it just flavorful icing?
Opportunity is pretty good in Limited and usable in Commander. But it's hardly ever been a Standard playable card. So how does Dragonlord's Prerogative stack up? Were it not a rare, I wouldn't care so much. The rarity is likely Limited influenced, as it is a strictly better version of an older effect. Still, drawing 4 cards at instant speed is awesome. This is a cute draw card with a seemingly very narrow additional effect.
However, Esper Dragons and Blue/Black Control ended up playing it on a regular basis with a fair amount of success. It turns out that 6 mana for 4 cards is always pretty much worth it, especially with no chance of being countered. With Dragonlord Ojutai and other Dragons seeing plenty of Standard play during the Standard heydey of Dragons of Tarkir, it pretty much never could be countered.
As for Commander, Talrand, Sky Summoner was one of the first Legendary Creatures to adopt it for his deck, loving the functional reprint of Opportunity. Niv-Mizzet the Firemind Commander players wanted it, too, as well as many other Dragon Commanders such as Scion of the Ur-Dragon, Dragonlord Ojutai, Intet, the Dreamer, and others. It's very good in the format, especially whenever you can make it uncounterable.
It's true that Dragonlord's Prerogative has relatively narrow playability due to it needing Dragons in your hand to be used to full effect. While I've argued in the past that this easily could have been an uncommon, that doesn't matter now that no one is drafting the set. The card does exactly what it was designed to do, give Dragon decks a fair, but powerful way to draw cards. It is indeed a Dragonlord's Prerogative to draw 4 cards and there's nothing you can do about it!