A change which was largely unneccessary and an aesthetic disaster.
Fact is, some services are not served by the unified theme and forcing them to comply has much the same effect of putting a square peg in a round hole.
Every organisation has a core business which sustains it and which should be protected at all costs. For Google that's Search. Diversifying your product offering, to complimentary products is one thing but this unification in a fruitless quest for social platform status is effecting the core business.
This is like a Dairy farmer diversifying.
First his produces cheese in addition to his milk. This is fine, good milk makes good cheese.
However someone down the road has a tanning factory and the farmer is jealous so he starts his own. Then he finds that his cows aren't the best for tanning so he changes the composition of the herd to suit tanning.
Problem is, tanning cows make lousy milk.
Facebook and google+'s brand of social networking are dinosaurs looking for a meteor.
Privacy and ownership concerns coupled with broadband expansion are going to force people to decentralize their social networking for their own security and peace of mind.