I could go for the second (size-based) progression. Is the storm done after that?
We might have a bit more work to do with it, but I think it's pretty complete once we put all the bits together.
So far we've got:
Void Storm (Su): A vacuum quasi-elemental can suck all air within the listed diameter into itself
as a free action? This process creates a wind of the strength listed in the Void Storm table below. All breathing creatures within the area of effect must succeed at a Fortitude save or suffer the listed damage due to air being ripped from their lungs.
A vacuum quasi-elemental becomes "filled up" once it has used its void storm for the maximum duration listed in the table - this duration can be divided however the quasi-elemental wishes over a 24 hour period.
Once "full", the quasi-elemental's deflection bonus to Armor Class increases by +3 for 1 hour?
This ability only works in regions with an atmosphere, such as habitable worlds on the Prime Material Plane. The save DCs are Strength-based.
Vacuum Quasi-Elemental Void Storm Table [TABLE="class: cms_table_cms_table, width: 500"] [TR] [TD]
Elemental[/TD] [TD="align: center"]
Storm Strength
Wind Force (Fort DC)[/TD] [TD="align: center"]
Storm Damage
(Fort DC)[/TD] [TD="align: center"]
Void Storm
Diameter[/TD] [TD="align: center"]
Maximum
Duration[/TD] [/TR] [TR] [TD]Small[/TD] [TD="align: center"]strong? ()[/TD] [TD="align: center"]1d4 ()[/TD] [TD="align: center"]10–20 ft.[/TD] [TD="align: center"]2 rounds[/TD] [/TR] [TR] [TD]Medium[/TD] [TD="align: center"]severe? ()[/TD] [TD="align: center"]1d6 ()[/TD] [TD="align: center"]10–30 ft.[/TD] [TD="align: center"]5 rounds[/TD] [/TR] [TR] [TD]Large[/TD] [TD="align: center"]windstorm? ()[/TD] [TD="align: center"]2d6 ()[/TD] [TD="align: center"]10–40 ft.[/TD] [TD="align: center"]10 rounds[/TD] [/TR] [TR] [TD]Huge[/TD] [TD="align: center"]hurricane? ()[/TD] [TD="align: center"]2d8 ()[/TD] [TD="align: center"]10–50 ft.[/TD] [TD="align: center"]15 rounds[/TD] [/TR] [TR] [TD]Greater[/TD] [TD="align: center"]hurricane? ()[/TD] [TD="align: center"]2d8 ()[/TD] [TD="align: center"]10–60 ft.[/TD] [TD="align: center"]15 rounds[/TD] [/TR] [TR] [TD]Elder[/TD] [TD="align: center"]hurricane? ()[/TD] [TD="align: center"]2d8 ()[/TD] [TD="align: center"]10–60 ft.[/TD] [TD="align: center"]15 rounds[/TD] [/TR] [TR] [TD]Monolith[/TD] [TD="align: center"]tornado? ()[/TD] [TD="align: center"]4d6 ()[/TD] [TD="align: center"]10–80 ft.[/TD] [TD="align: center"]20 rounds[/TD] [/TR] [/TABLE]