He was sure stronger after his ROSAT trip but that may have been reckoned because goku overpowered M.zamasu's holy wrath by himself while vegeta needed trunks's help,or maybe goku bridged the gap? what do you think?
I was browsing Db wiki (yea i am stupid for doing that) and i stumbled on this .Fused zamasu is 3/4 Shinjin-1/4 Saiyan.HOW IS THAT POSSIBLE!??!?!
Zamasu is a kai and goku black is a saiyan (saiyan body) so the result is 1/2 Kai and 1/2 saiyan.