The residents of South Melbourne and St Kilda won’t be impressed. It will add significant time to their journeys. If for instance you currently catch a Route 12 tram from the Exhibition Street stop you will now have to walk 3 blocks up Exhibition Street to La Trobe Street, only to effectively travel back on the tram to Collins Street (the Spencer Street section from La Trobe to Collins Street). What will happen in practice is that most passengers will interchange at Collins & Spencer Streets, filling up the Collins Street shuttles that replace the Route 12 trams. Similar happens at the moment on Route 58, the (temporary?) amalgamation of Routes 8 & 55. Most passengers from Toorak (the old Route 8 via Swanston Street) get off at Domain and catch a St Kilda Road tram. Route 12 is primarily to service the above areas, not form a shuttle service for La Trobe Street.
Another minor aspect of changes is there will no longer be a connection from St Vincents Plaza and La Trobe Street through to the top end of Docklands – Central Pier & New Quay. You will have to interchange at either Spencer & La Trobe Streets or Collins Street & Harbour Esplanade.
Routes 12 & 30 should be left as is. The proposed peak-hour Victoria Dock – Preston (Route 11A?) trams should run from Docklands - Waterfront City or Central Pier via La Trobe Street (Route 14) instead. Some Collins Street shuttles (Route 9 or 10 Victoria Dock – St Vincents Plaza) could be added between inter-peak and, perhaps, early evening and weekend hours. Consideration might be given to moving the St Vincents Plaza siding from the north side to between the Up and Down tracks, a la the Arts Centre, albeit with gentler curves.
As discussed above, using ‘A’ for a regular route is rather confusing. ‘A’ should be used for temporary alterations, eg Route 96A when it runs via La Trobe Street. There are plenty of vacant route numbers with historical association that could be used. East Malvern Routes 3 and 3A are confusing enough. What happens if Route 3A gets altered temporarily? Since it is now the only 3-digit number, Route 109 should be renumbered either back to 42, or 44 (since it’s a bit longer at the eastern end). Shouldn’t cause too much confusion at the 'Borough' end.
It would be interesting to find out how much of a net gain this is, eg replacing a 19-hour-a-day 7-days-a-week Route 30 service with a vaguely worded ‘up to
19 hours each day’ Collins Street shuttle. It's hard to imagine a shuttle running up and down Collins Street at 10pm on a cold winter’s Monday night when there are Route 11, 48 & 109s also running. It seems more likely to be a Mon to Fri inter-peak service.