Take it just a little further: why not ballistic flight? Sure, they call it the "vomit comet" for a reason but with the right marketing and some investment in gravol, I feel like the zero g portion of the flight should be a selling point.
There's also no reason to keep everyone in the same capsule once you're in space: you could have multiple independent reentry vehicles. Fire off a rocket somewhere West of Chicago, send a dozen people to Stockholm, a dozen to London, a bit of cargo to Prague.
As long as nothing ever seems to be mysteriously off course and heading for Moscow it sounds like a great idea. Is it easy to distinguish a ballistic missile full of passengers from the more bad kind?
Fit them with transponders and broadcast schedules well in advance of flights. The destination can veto a flight at any time before launch, and have inspectors at the point of launch. In this way, Moscow (etc) could keep arrivals down to a limit that their antiballistic defenses can handle, and ensure that only people-carriers are being put into their airspace. An attacker would be limited to a single kinetic suicide attack before their target goes on high alert.
But I was more curious about the fuel efficiency...
