Pokemon Go has a new king of the hill, which a lot of players still won't want to use.
One of the 50 new Pokemon introduced to Pokemon Go earlier today is the insanely powerful Slaking. Slaking has a top tier CP and an Attack stat comparable to Pokemon like Mewtwo, Alakazam, and other typically OP attackers. It also has a Stamina stat that's just a bit below Snorlax, meaning it can absorb a ton of damage. Slaking is also a Normal-Type Pokemon, which means that it's only weak to Fighting-Type attacks. But that's something that Slaking can counter with "Play Rough" attack it knows as a Charge Move.
Basically, Slaking is unstoppable...or it would be if it didn't have a critical flaw. Pokemon Go slowed Slaking down by giving it only one Fast Move: the new "Yawn" attack. Yawn does ZERO damage and only gives players a little bit of energy towards its Charge move whenever its used. That means that a Slaking has to absorb a lot of punishment from enemy trainers before it can use a Charge move, which should give a lot of opponents an advantage in battle.
The main series version of Slaking has a similar nerf in effect via its "Truant" ability, which limits Slaking to attacking once every other turn. Although Slaking has amazing stats, its laziness prevents it from ever being useful in a serious Pokemon battle.
Since Slaking doesn't have a viable Fast Attack, its usefulness could be limited in gyms. After all, even Blissey can use Fast moves in battle and can absorb the same amount of damage. Still, there are probably circumstances in which Slaking could be useful...especially in raids where getting off Charge Moves is critical to success. After all, unlike Blissey and Snorlax, Slaking's charge moves will do some real damage, so that might outweigh the fact that it can only make an attack every few seconds.
We'll see how Slaking has an effect on the Pokemon Go metagame. In the meantime, go out there and catch those new Pokemon!