I have few thoughts about this.
1) separate {jobname} input filed, with something like {jobname} variable getting populated with the text from the field. Default keyboard focus in Ingest window. Although a bit specialised and relying on variables = made for power users. I would love it, but do not know about not power users...
2) colour highlighting. How about (dunno if possible in text entry fields on both OS X and Win) colour highlighting variables and other text, with variables getting truncated in the middle and the last text visible at the end, in the input field?
Like this:
{datesort}_{timesort}_{serial ... }_JOB_NAME
Just an idea. Frantisek
P.S.: Now I think about it, syntax colour highlighting would be great for all input fields where one can enter variables. Although again only useful for powerusers. Your variables are so great feature, please consider revamping the UI for them to make them more accessible, somewhat akin to Spotlight interface in Finder, where one can press the + button on screen to add another criteria from the list. It would make it IMHO more accessible for more casual users.