OG - As a coaster, TOTII is sorely lacking.
When it was built, it was a great attraction, a record breaker - but in reality - it's experience is nothing more than a relatively fast shuttle coaster - without inversion, or any particularly good experience. It is the quintessential 'one-trick pony' fast-up-down-brakes... and quite obviously so - with the need to 'reinvent' it by reversing the car.
If that is Dreamworld's Signature Coaster - it's probably quite fitting - relatively good at going fast in one direction, followed by slowly going backwards the same way that they have come. Most of Dreamworlds more modern additions are one-trick ponies. They've certainly tried to shake off that image of late - giving love to old classics - but when I think 'signature coaster' I think i view it similarly to the OP - a full circuit, experiential coaster that has infinite re-rideability, and is what the park is renowned for. You need ALL of those factors for something to be considered the park's "Signature" in my opinion.