Teferi, Master of Time

The static ability is the whole design argument, and it rewrites how a planeswalker occupies a turn. Every prior planeswalker got exactly one loyalty activation, on your own turn, at sorcery speed: that constraint is what balanced the card type, because it capped how much a walker could do per rotation and gave opponents a clean window to attack it. This one activates any loyalty ability at instant speed on any player's turn. The practical consequence is that the plus ability can fire on the opponent's end step, meaning the walker gains loyalty and cycles a card while the summoning-sick threat behind it never gets a turn to swing, and both players' turns become live windows for the minus that phases out an attacker or blocker. Phasing is the deliberate choke on the removal ability: it does not kill, it does not exile, it just makes a creature cease to exist until its controller's next turn, so it buys a combat step rather than solving a board. The ultimate hands you the payoff the color has always coveted, and instant-speed access to loyalty abilities is the mechanism that gets you there faster than the card type usually allows. What makes it a genuine departure is not the numbers on any single ability but the timing rules bolted around all of them: it took the one restriction every planeswalker had shared and simply removed it.