At the top of dashboard.el many libraries are loaded immediately.

(require 'bookmark)
(require 'calendar)
(require 'page-break-lines)
(require 'recentf)
(require 'register)

I'll pick on recentf but my argument follows for any of the other libraries:
Loading recentf immediately like this is not optimal because dashboard does not even know whether recentf will be needed yet. User's that prefer not to include recentf in dashboard-items shouldn't have to play the additional startup time for requiring it.

Doom's dashboard , as an example, does not require anything. It's only dependency is the icons (I actually think this should be an optional dependency as well, but I digress). It would be nice if dashboard by default did not require anything, but would only do so if the user specified.