It's too difficult for us to say in advance which apps will be included in the near future and which won't. There's lots of unforeseen problems that can be encountered that make these predictions impossible. I can say that Dolphin is not an app we're likely to add next, there's a few that we've seen many more requests for.
PrestaShop is a lightweight open source e-commerce shopping cart system that we added to Installatron earlier this year. We had a number of requests for it, and it filled a gap in the applications we include. We don't like adding apps that mirror the functionality of other apps--it's just needless confusion for endusers.
Of course, if you're keen to add Dolphin right away, we do have an Installer SDK and a full GUI Installer Editor to enable the creation of custom installers with minimal programming knowledge. See:http://installatron.com/sdkhttp://installatron.com/editor