My personal approach to this would be to push it outside of Tableau, there's just so much input.
I would create a web application for maintaining these input parameters / factors and then connect my data together in a common database. This would allow the user to update on the web, then refresh in Tableau and disassociate the input from the review (which I personally like).
Obviously that wouldn't be available to everyone, so a trimmed down approach would be to use an Excel Sheet or Google sheet for the factors instead.
If you absolutely have to keep it within Tableau, I would reconsider the need to have everything on the same page. What's more important - responsiveness and speed or the ability to see it all at once?
Yep, customer wanted it all in 1 platform so they didn't have to go into several applications, wanted to see the change immediately without having to rerun extracts, etc.
In the past we levereaged SP and brought in external data that way, but this case - they would like it all to be a part of the dashboard and not with the use
of another application. Agree with you though - speed / responsiveness definitely outweigh a funky look.