These are my suggestions on what the best fitting vehicles would be on most services. I am not predicting that these will happen, this is just my opinion on what types of buses should be allocated on what types of service.

X11- Just keep the X-Lines X9/10 and spares.
B1- Keep the Northern Versa.
ToonTour- Keep the open top Presidents (obvs)
AD122- Keep the Solo SR's but they should refurb the insides as they are getting a bit old.
X1- Def keep the Streetdeck MH 3 for now but in a few years they should upgrade to E400MMC.
X5,15- Keep the Streetdecks but maybe redo the seats into the 2018 red and blue leather as the plain blue ones still have the old logo on.
X6- Keep the Optare Solo SR.
X9,10- Keep the Elites but in a few years they should upgrade to better coaches.
X20- Get rid of the Citaros and upgarde to E200MMC.
X21- Upgrade to Streetdeck MH 3
X22- Keep using the spare X-Lines Gem 3
X30,1,2- Downgrade to Streetdeck MH 3, swap with X1.
X45,6,7- Keep the Streetdecks.
X66- Keep the Streetlites but rebrand as intu doesn't even own MetroCentre anymore. IMO they should bring back CentreLink.
X70,1,2- Keep the E400MMC.
X84,5- Keep the E400MMC.
1A,B- Keep the Gems but refurb them with the red seats and also get a new livery as the current one is getting a bit old.
2, 2A- Keep the Streetlites but get a new livery.
4- Get the citaros from X20 as they have the leather insides, and repaint the current ones into 2019 FL.
5,5A- I dont really know just keep whatever they have rn.
6,6A- Keep the citaros.
8,8A- Keep the streetlites.
9- Upgrade back to citaros but dont have a brand just 2019 FL.
10,10A,10B,10X- Upgrade to Streetdecks.
11- Keep the Solos.
12,12A- Keep the citaros.
16,16A- Keep the streetlites.
19- Keep the Solos.
20- Upgrade to Citaros, those streetlites are so thrashy on the A690.
21- Upgrade to E400MMCS.
25- Upgrade from those boring Versas to some Gems. 25 is getting way to busy for single deck.
26,7- Keep the Gems.
28,28A,28B- Keep the versas but I bet they wont last for long. After that I have no clue.
29- Same with 28.

I don't know anything about 30-40.

40,40B- Keep the Solos.
41,42,42A- Keep the Solos.
49- Keep the Streetlites but brand it, with an actual name not just "The 49".
50- Get rid of those terrible Omnicities and get some Streetlites or something.
53,54- Keep the Yutongs, nout wrong with them.
56- Get Streetdecks.
57- Rebrand and upgrade to E200MMC.
58- Keep the Gems.

ALL INDIGOS- Keep the Solos (and little pinks)

Cant be bothered to do the rest.
Share your opinions.