Have you considered the Sofitel Sydney Wentworth? I stayed there back when Accor was selling rooms at $200 AUD/night and liked it quite a bit as a Platinum. Crucially, the hotel late last year completed a major renovation so your experience could be quite good.
One point about the Sofitels, they are a nice hotel to stay at, but the experience is elevated considerably if you hold Platinum status as you'd have access to the Executive Lounge (an experience on its own with dedicated check-in and check-out areas meaning you don't rub shoulders with the commoners on the ground floor). You also tend to get a nice room too.
Other thing to consider is looking at what the Accor+ rates are. I've stayed at a number of Accor CBD properties where the Accor+ rate was hovering around $120/night (one recommendation I can recommend is the Hotel Morris - it's a boutique hotel but the breakfast was a nice a-la carte set up none of this buffet nonsense). Best of all, you can get cash back at Accor with the current offer I'm seeing
being 6.5% back on bookings. One more point, and I know some will poke fun at me for saying this, but have you thought about the ibis Sydney Darling Harbour? It's located right beside the Sofitel, tends to have rates in the $100 range (sometimes less) and has a better view of the harbour as there is less construction blocking the way.
-RooFlyer88