If you've used the SDK, you'd see how hard it is to use. And I'm not calling Freespace half-assed; it has a fully featured, easy to use mission editor. Hammer is notoriously difficult to even comprehend.
And of all those "mods" - that's for Half Life 1. Go check for Half Life 2, and see how many good major mods have been released...like....two.
And Freespace (I'm coming back to it because I couldn't fit it in up there), has a perfectly fine system. You can do virtually everything the devs did, without code editing, it's easier to edit, and like I said above; there is a complete and TOTALLY operational mission builder that is very intuitive.
![:v:](https://www.hard-light.net/forums/Smileys/HLP/v.gif)
obviously spent time coding it and making it user-friendly.