The "Values" field of the "Get User Input - Choice" action has a character limit of 64, which limits the maximum amount of choices in the dropdown on the dialog it spawns(32 total; 31 single character choices from the "Values" field, and 1 from the "Selected Value" field).
Could this limit be expanded? I don't know at which point it would become a performance issue(though I would hope the option to stuff 1073741823 choices into a single dropdown is probably not necessary).
EDIT: While maxim length varies, the ones that accept text, and where it would be most beneficial do have increased capacity. Numeric fields don't validate input, but they do indeed accept tokens, so that's to be expected.
Tested with v1.7.5.45