except the idea that you can anticipate in what directions your software is going to grow

It's ironic that I should be suspected of claiming that. Let me reassure that you on this point, we agree as well. (It's looking more and more as if we have no substantial disagreement.)

My point is that the risk is perhaps lowest if you are going to add the second pie chart, but if someone else is, the three-screens-long function could be riskier than a slightly more factored version. Or not: there is no general rule involving only length.

If you want to make a pastie with that function I could give you an actual opinion. ;)