There are 3 things that I think should be included with Dolphin as part of the default package.
1 - recurring payments. Little point having membership system so integral to the whole script, if there is no way (other than 3rd party) to take recurring membership payments.
2 - photo uploads in forums, not just url links.... PKForum 'fixes' this, but this is one thing that should be basic to Dolphin.
3 - A Chat module that is not flash based so will work on all mobile phones.

All these things see more have been bought up time and time again on the forums here over years... should be included as standard package.