It really depends what you call more support. It is interesting to look at race engineering in that context. Nico got their most experienced man (Jock Clear) who engineered both Villeneuve and Button to world championships. Schumacher got Andrew Shovlin who is vastly less experienced.
One can interprete the race engineer pairing to be an advantage for Rosberg, but then we would probably neglect that Schumacher is constantly on the radio with his engineer and is used to talk a lot to the team. One part of Schumacher's race craft is his ability of multi tasking. He does fast laps and constantly keeps talking on the radio getting updates on anything from the sensors of his car over the weather developments and observations about his competitors. Fisichella for instance does not do this. He famously claimed unexpected radio traffic when he went off track once. I do not know if Rosberg has the same communication habit, he probably does that to a lesser degree than Schumacher. If I would have to make a guess how Brawn's personal split of in race communication with both drivers will be I would think it will be probably 70% Schumacher vs 30% Rosberg. You may call that unfair but it is practically unavoidable given the habits of 15 seasons in F1.
Considering all aspects I would still call the situation over all fair.