He hasnt met an opponent we know of that would require him to use shadow clones. Also, for those sayin he has has no chakra;
He did S/T a TBB
Summoned Gamabunta
S/T Kurama itself
Put up a barrier
Sealed some of his own chakra and Kushina's in Naruto
Used Dead Demon on Kurama and took HALF of the biggest chakra mass with him to the underworld.
Summoning Gamabunta is shown to be incredibly taxing (what Jiraiya said); most people would lost like half their chakra.
Using S/T on something as HUUUUGEE as a TBB or better yet, KURAMA ITSELF shows Minato has good/great chakra reserves; many times Kakashi's.
Also, 1 shadow clone pretty much doubles his potency; if people cant touch the original, how would they touch a clone (same intelligence etc.)? However, for me, a jutsu that would come in handy for him would be a kunai shadow clone (similar to Hiruzen's shuriken shadow clone). Im sure (non-canon) he's mastered this; again he hasnt met anyone who's been good enough for him to use his other techs on.
P.S Im sure the guy has 2/3 elements and has quite a few other jutsus up his sleeve.