I don't say all of this features should be here,but I suggest several ideas to upgrade the overall look and usability of scripts submissions.
a choice between adding a preview or not.
Confused it with embedded pictures, though it being a preview will be also good.
Idea 3 (Probably not, because of possible abuse,but still)
A choice to upload the scripts as an archive if there are several files,or there is a more suitable specific for the game format. (For example .vpk in HL2)