I have never eaten at The Waiting Room, so can't vouch for its quality, but I have walked past many times. I am happy to "go with the flow" regarding venues. There are plenty of places in and around the casino complex.
The Crown Casino complex is huge. It is not my favourite place, but it is worth a visit to say you have been there. Crown is the largest casino in (Melbourne / Australia). The main gaming floor is rather large. It is a good walk from end to end. The "real" VIP tables are tucked away on a different floor away from prying eyes. There are many restaurants & bars, several nightclubs, numerous function spaces, a cinema, a bowling alley, a gaming arcade and more. The "gas brigades" (fire towers) along the river promenade are a crowd pleaser.
(Link). Search for "Crown Fire Towers" for some good YouTube videos.
If the weather is good, the areas along the river are lovely in the early evening (Southbank promenade / Crown Casino promenade / South Wharf).
My friend plays an acoustic set at one of the bars on the gaming floor on Monday nights from 6-9, if anyone wants to hear some tunes.