Last I heard, the official line was that it'll be a route-by-route decision.
What criteria will be used for route-by-route assessment? One would think that those routes which were last to be converted from the one-and=only true Routemaster were those on which the hop on/off principle was most established and therefore most needed now, if need is the right word.
Looking at those last dozen or so routes, each passed or reached one of the two Circuses, Oxford or Piccadilly, indeed the Piccadilly thoroughfare itself ten years ago was hosting six routes, all of them RM. Oxford Street, Regent Street and Piccadilly with their traffic lights every few yards would seem to be no-brainers for conductor operation, but it doesn't look like TfL feel that about the former, particularly now the 8 won't receive conductors (yes, I know it's currently cut back). I await the decision about the 73 and if that is operated without conductors I think it can be said that they're on the way out as soon as Boris considers he can save face.
Regarding the 23 route, on the mock-ups and presentations this looked like it would be one of the first. Could it be that Tower Transit have said 'no thanks' to them and also continuing to operate the 'Heritage' 9. The only time I travelled on the latter was a few weeks ago on a Saturday, when I watched the bus I wanted to catch go into its Trafalgar Square terminus and only reappeared after a 25 minute wait. Any fears of the bus being crockrd were allayed when its driver, a man of mature years, proceeded to get us to Kensington, Holland Road in less than fifteen minutes, including a u-turn onto the stand with me on board! The most high-speed ride I've had on a RM since three of them on route 3 decided to race each other along Croxted Road, ending with the one on which I was the sole passenger crashing into a builder's skip inconsiderately left at the side of the road.