>>51730487So you're saying that something with even better offensive stats than Deoxys-A would still be shit because it dies to priority moves due to its ice/rock typing.
I'd say that would be an easy AG if it has a Deoxys-like movepool.
Now, answer this: what if, say, ice/rock it was any other type with multiple priority weaknesses?
Say rock/dark, or ground/flying. Those are usually considered decent defensive types due to the mons they are on. But those mons happen to have good defensive stats as well.
Suddenly those typings aren't so defensive on a glass cannon.
Imagine if Deoxys-A was ice/rock, it would functionally be the same thing just with different checks. Same if it was any other type.
In short: the more a pokemon is designed as a fast glass cannon, the less the defensive properties of its type affect its role.