Yeah, the drillworm really ought to drop some tasty fillets if you ask me :P
They don't even have to buff the existing foods THAT much to make them useful. If, say, Dwarven Stew granted 15% heal, +10% earth resist, and +2 strength as a base bonus, it would be very solid use of 1 AP (if not a bit OP at that point, may need just +1 strength) with 5 star diner doubling those quantities.
Another idea is to make each food buff permanent until you eat something else, when it will go to a 5-6 turn duration. This will let you prebuff a little depending on the fight. But there definitely should be a penalty for eating too many foods (3-4+) at once (like, a poison resist and move speed penalty :P)
