One move that this game could really use...

[Blaziken257]

...is a Grass variation of Stealth Rock. I never really liked the idea of Stealth Rock, because unless you have Rapid Spin, using Fire, Ice, Flying, and Bug-type Pokémon are tough, especially Pokémon that are quadruply weak to it. So, having a Grass version would probably balance this out. And if there is one move of this kind on the field, using another should replace the first move, as opposed to creating an additional layer of damage. In other words, there should be only one type-based move that damages upon switching at a time.

Grass is a good type to do this with, too, since Grass is kind of an opposite of Rock. Rock is good against Fire, Ice, Flying, and Bug, but Grass does half damage against three of these four types. Rock is also weak against Ground, but Grass is good against it, and is also good agaist Water and Rock itself, which helps to "balance" them out a bit.

Now, for some reason I don't see this happening, and some people will probably ridicule me, but this is what I think of it.

 

[Ivysaur]

You did a great job on the that long and very well thought-out post, but we have a thread specifically for suggesting new types of moves.

 

[F-22]

Absolutely not. We don't need more entry hazards of any kind, regardless of type, regardless of the "catch". What we need is more Rapid Spin-like moves.