One important piece of information (at least for me) that gets lost when exporting psdata to MAT or CSV is the time-stamp of each waveform in the file.
Adding it to MAT files should be very simple, since the datablock definition is very flexible - just add another data block with this info.
For CSV file this may be a line at the begining of the file.
By the way - The time-stamp in PicoScope is at a resolution of seconds - I do not know if it is an inherent limitation, or just a matter of rounding up for display - if it is the latter, I think that there should be an option to display it at the time resolution that the system saves.
Is it possible that you will add this data in an upcoming revision?