If your breaking into types, then consider this:
-Rock canbe considered Ground since sediment in the ground can be formed to make Rocks.
-Flying can be considered Normal as well.
-Ice is a part of Water.
As an example. I personally think new types are a good thing, if done right. These are types I think are good, if they follow these guidelines:
-Wind: Wind-Type isn't to be confused with Flying-Type. Certain Flying attacks such as Gust, or Whirlwind, are better suited to be Wind-attributes as they have no relation to Flying other than the use of wings to cause them. Also, certain Pokemon (Castform and Drifloon), are better suited to be Wind-types.
Weaknesses: Rock, Poison, Psychic, Flying
Resistances: Ground, Grass, Ice, Bug
Advantages: Fire, Bug, Ground, Grass
-Cosmic: Cosmic covers a whole lot of Pokemon whom, by PokeDex descriptions, come from outer-space (Cleffairy, Deoxys, etc.). Cosmic and Psychic aren't the same because Psychic power comes from the mind, not space. Besides, Cosmic seems to be more and more neccesary, with Palkia, Deoxys, and Jirachi being introduced all as Pokemon with a strong affiliation with space.
Weaknesses: Dragon, Steel, Electric
Resistances: Psychic, Dark, Rock, Water, Ground, Grass
Advantages: Psychic, Rock
-Light: The Light-Type I'm talking about has no connection with Electric, Fire, and Psychic. Light-Types are essentially Pokemon that repsent purity or innocence (Togepi, Milotic, Igglybuff). Such Pokemon exsist an every generation, and we need a counterbalance to Dark-Type. Some argue that Dark is weak to Fighting because Fighting represents the old Hero v.s. Villian thing, but Heroes have to be good in heart too.
Weaknesses: Dark, Ghost, Poison
Resistances: Fighting, Psychic
Advantages: Dark, Ghost
There's my two cents.