Hi-
The problem is that a List Form has a locked schema - that is, the schema is intrinsically locked to the SharePoint list.
If you design the form, and start adding controls, you're going to run into issues because there is no location in the SharePoint list to store these items.
You would need to modify the SharePoint list, then design the form, and the InfoPath form will show the controls needed for the SharePoint list and its columns.
You also cannot add code to a SharePoint list form, so that prevents you from doing more complex things via code.
So, to summarize, SharePoint list forms are very limited. If you need repeating data, if you need to submit to SQL, or use code... then a SharePoint list form is not the answer. Good luck!