Hi Karen,
Just adding my voice for the Product Managers to hear that we also would like some sort of enhanced display logic to be supported by Workfront.
We use ServiceNow for our support operations, and it works nicely in that you can have Field A, and depending on what is selected, a specific set of options is presented to users in Field B.
The way Workfront currently works is that Field A and Field B are fixed lists, and then you run into the issues you're encountering where you have to have huge global lists of options. The only other workaround is to have a different field (e.g. B, C, D, E F) for each option in Field A, and then use display logic on the custom form. i.e. if X is selected in Field A, then display Field E. Then you'd have to use a calculated field to sum or concatenate the results into a Field G which is the actual field you use for reporting etc.
It would be better if some enhancement work can be done in this area! :)
Regards, David