Broadly speaking, I'm very cautiously optimistic about the Olympics coming to Brisbane in general. The IOC are moving away from a host-city to a host-region model as part of their "2020 remodelling" strategy after the viability of the Olympics came into question. The government seems to think the games will pay for themselves, but that's also something that's been heard all before.
If a developer were to time it right, there's a great opportunity to strike with a Brisbane or Sunshine coast based theme park that has the potential to really leverage the Olympics for long term exposure, but beyond that I don't see the Olympics moving the needle enough for specific tourism operators to benefit wildly after the games are over. Like @Gazzasaid, with the Commonwealth Games, the messaging was so strong about transport and roads being congested that everyone avoided the Comm Games like the plague and the polar opposite happened.