I agree with you on this, but when I watched Sonny playing for WsM against Taunton recently he seemed to me to have beefed up a bit since I saw him previously.On the Watkins at WSM comparison:-
Ollie was 19 when he came back from WSM, Sonny is 17.
Ollie started 18 games scoring 10 goals, Sonny has a handful of starts/goals.
Ollie jumped two divisions from WSM to City, Sonny would need to jump four divisions, as WSM are playing a league below where they were in Ollie's time
As others have pointed out MT has opted to sign three loan strikers to back up Nombe rather than using Sonny.
When I last saw Sonny play (an U23s game?) he looked miles off being physically ready for League Two.
I'd love it if he was ready now, but the evidence isn't there yet.
Hopefully this will continue and coupled with his technical development all being well he‘ll be ready for us before too long.