I think your rant is somewhat misplaced as inferring the user desire in this case is not always possible. In general, I find it to be dangerous behavior when merely adding data changes formulas. I think the proper action is to insert a row.

On the other hand, having defined tables with in a workbook is great idea, but it makes the whole application a wee bit more complicated. I'd like to see it in something of a hybrid between Access and Excel, where you can mix structured and tabular data.