Ok, I know I shouldn't wade into the child support discussion, but since you asked...
I think the reason we usually hear such different reports on child support is because, first, state laws vary wildly, so what is reasonable in your case could be a much higher or lower number in another state. Also, in some states (like Texas), it is a flat fraction of income of the NCP. In most familes, I would guess that the less money you make, the higher fraction of it you are likely to spend on the kids. I mean, yes, you can spend way too much on kids' clothes, but there is a realistic limit. So, in Texas at least, you pay a fixed percentage of income. The moms with low-income exes then get very little money, and struggle financially, while those with higher-income exes get more than they could realistically use on the kids.
And, no, the mortgage is not just for the kids. The difference between a two and three bedroom might be, but single women need houses too, and those of us without biological kids don't just live on the street, nor do we get to downscale to one-third of a car. Plus, the NCP has to have a place for the kids to visit, and a car to transport them, and they don't get support.
Child support should support additional expenses due to having kids, not the stuff adults already need. I know how much my expenses go up when we have the kids for the summer -- we buy more food, whole wardrobes, and some fun activities. It doesn't even begin to approach what we send in support. Further, we still have to send those checks even when we have the kids for months at a time.
I think if I were writing one I'd have day care separate from child support. DH's ex has subsidized child care at work, yet we pay child support that is supposed to cover everything, to it basically assumes a day care amount. Also, when we have the kids for the summer, we have to pay day care, and we don't get child support. Sometimes their mom will drop them from day care if we have them even for a week, so that was always a financial disincentive to see them for that long of a stretch. So separating those would probably make it more fair and lead to less resentment.
Oh, and pick up/drop off -- in Texas, it's all the NCP -- door-to-door service from him. I think it should be more evenly divided. For example, if she'd take the kids to the airport instead of making my husband have to have several hours between flights, rent a car and child seat, and go pick them up, that would help. Though, things are changing, and she is having them picked up this time, sometimes it's easier to have the expectations in writing from the get-go.