I would just like as simple an input syntax as possible (minimum of punctuation) for interactive use, for both lists and tuples. For instance, if all entries in a list or tuple are numbers, then I think eliminating the commas would be convenient and look nicer.
As a use case, one might have
" permute (2 3 4) [7 9 11 0 1 5]", which would be a function which cyclically permutes elements 2 3 4 of a list.