>>12986469Two examples:
Some types (let's use Ice and Poison) are pretty weak and have been slowly falling behind for the last few years, and are both largely outclassed in their roles by Pokemon with different types that can use moves of that type (Water types with Ice Beam, almost every Pokemon with Toxic/Toxic Spikes). Gen VI has to be for those disadvantaged types what Gen V was for Bug types.
(In a side note, Stealth Rock (and the idea of type-based entry damage) is a horrible plague on the metagame that should be corrected)
Weather is completely imbalanced. Rain is by far the most useful effect with tens of Pokemon benefiting directly through Abilities alone. Sun is 2nd but there are much less Pokemon that benefit. Sandstorms deal damage and raise Rock-type's Special Defense (and is notable for having a whopping two non-Legendary Pokemon that can induce its effect), but is otherwise only useful for countering other weather-based moves and abilities. Hail also deals damage but the damage is only ignored by Ice-types which means your team has to be hyper-specialized to take advantage of it, it has very few abilities that make use of it (which are weaker than their counterparts), and provides no direct benefit for all Ice-types unlike Sandstorm.