Here are some features that I heard others suggest in SL, and some features of my own.
Functions
llList2Notecard - Input a list into a notecard, with maybe a 'clear' option?
llNotecard2List - Input a notecard, line delimited to a list.
llInput - Simular to llDialog, except an input box.
Objects
In the "Next Owner Can" area, a box that would say something like "Apply To All Prims/Content", so that "Next Owner Can" options can be set to all prims and content within that object, rather than going to 1 prim at a time and setting perms on each prim and scripts in that object and prims. (EG 205 prim Roulette Table... 150 or so of the prims being scripted...)
Misc
Purhapse an easier way to detect if items are potential for sim lagging?