What you're describing is the Terran Federation from Blake's Seven.
What about population control between ones legs?
I can see idiots who can't manage their contraception being shipped off to a colony.
Besides, Earth isn't really Earth.
Most of the landscape would be the administrative and regulative bodies for the Federation.
Millions of office complexes.
When they were figuring out division of labour for the Federation in the beginning, Earth was the ugly redhead. Politically young and technologically pathetic, they were the only power at the table who could be trusted to act as the seat of the Federation because they were the most powerless to take advatage of the situation.
Although they wouldn't hand over Earth outright, I can see a series of hundred year leases which are renewed amid a huge amount of yelling as the Federation et al has to hand over god knows what to "humanity" to keep their government in working order and the Earthlings off Earth.
Not too dissimilar to the debt ceiling crisis and the sequester in the US of Late.