I agree with Zarcon, Houston etc etc,
Before adding extra features, please give us a stable core and make all the standard features work faultlessly. Make Dolphin something to be proud of.
Adding more features to a script that still doesn't work how it should, makes no business sense and shows a total lack of consideration for the hundreds of thousands of paid up users, who would love to be able to relax and not constantly worry what is going to go wrong next.
Dolphin is a good script, but see more it could be an awesome script and sales would easily exceed your membership targets if everything worked and people had more confidence in Dolphins capabilities.
If things are to be added, surely there's no need to ask, just browse through the forums to see what members have been asking for 'over and over again' for years and add those functions.. Such as easy upgrades from any version to the latest, adding rows in page builder, better advertising module, more user types besides M F or couple, functional forum, better cache clearing, etc etc etc
Better still, restore some of the functions that were already present in earlier versions of Dolphin, but were removed so that we now have to pay for mods.