I don't think that there are further wildcards available and that you could apply any regex-logic by loading files. I'm not absolutely sure but I believe that Qlik has no own logic for handling files else they just use windows dll's for it and AFAIK there are also only * and ? as wildcards defined.
Beside this I don't think that a for each approach with dirlist/filelist is ugly. It's fast and quite often there are further conditions like checking the filetime/filesize, handling different data-structures, file-formats, where-clauses and so on - and at least there you will need some more efforts to implement it.
Further the help-example for the loop indicates by using sub-routines how it could be nicely handled - means putting everything in a routine which again called the necessary routines and this could be put in an include-variable and used globally within your whole environment. And then its just enough to call the routine with the needed parameters.