1)
In LibreOffice there is no way to customize chart layouts or even make new ones. E.g. line thickness is pre-set to "0.08cm", icon width and hight are pre-set to "0.25cm", etc.
An option to modify these values for each chart type or (even better) an option to make new chart templates would save the user a lot of time. This should also not be restricted to only a subset of settings but everything should be customizable (e.g. start axes at "0" but have the maximum set to automatic, ...).

2)
Upon clicking the chart button, Calc always starts with the first chart type "Column" and the first layout "Normal". It would be very helpful if Calc would automatically choose the last used chart type and layout, e.g. "XY (Scatter)" and "Points and Lines".