I thought the maw expands over its reach, doesn't it?
So how about 60 ft./60 ft.?
I'd rather give it an "engulf" type special attack with a variable area, either based on Hit Dice.
Maybe a 150 ft. cone, increasing by 50 feet per 10 Hit Dice of Advancement, with Advancement of 30-100 HD?
You mean like Vortex Maw?
Engulfing Maw (Ex): As part of an attack or full attack action, a draedan can stretch its vast maw to cover an area 50 feet in diameter anywhere within its Reach. All creatures within the affected area must make a DC 67 Reflex save to avoid being scooped into the creature's expanded, open mouth and swallowed. See Swallow Whole, below, for the consequences of being swallowed by a draeden. The save DC is Dexterity-based.
Vortex Maw doesn't sound right, since it's not sucking things in. You must mean the draeden's Engulfing Maw:
But we only let that swallow within a 50 ft radius. It seems a stretch (pun intended) to let nay-churr engulf a larger radius than a draeden, or to engulf outside its reach.
I thought we decided any more than a 50 ft engulf radius was too overpowered, even for a draeden...