Thanks a lot for your reply Chris! Looking forward to it.
If you do start playing around with custom fields, another great feature (which is much more testimonial appropriate) is an admin_rating for a given testimonial. This score is given by the admin on how useful the testimonial is and could then be used as a new ordering option
[strong best] instead of [strong newest] for example
To illustrate “They are good” might get an admin rating of 1 while “They are fantastic, I highly recommend them” might get an admin rating of 3 so that it is more preferentially displayed.