This and atmosphere hopping space planes both have the same drawback: a significant number of people vomit on their first weightless trips. Do you really want to ride packed into coach in that kind of environment?

I guess with enough frequent zero-g points you could upgrade to the "no hurling" section.

(The not-quite-straight-through tunnels wouldn't be fully weightless, maybe we should concentrate on those. Then we just have to solve the insurmountable temperature, pressure, and vacuum problems.)