The Italian international, 22, will complete his move from Eastlands to AC Milan today for £17million, with a potential £2.5m in add-ons.
Balotelli scored 30 goals in 80 appearances during two½ years in Manchester.
But Royle, also a former City player, rapped: "I will only remember Balotelli as a great penalty taker.
"He's got great style with those, he leaves it very late and is a wonderful penalty taker.
"Apart from that, though, I've never really understood what all the fuss is about.
"He's got no work-rate, I've never seen a player walk so much as he does on the pitch."