I have a text column that has formulas and conditional formatting already added to it preventing me from changing the column type to a dropdown list.  It is spread across several years of spreadsheets making a larger conversion to a list time consuming. 
I have a request for Report Filters to have the drop down list similar to the spreadsheet level filters.  Is there an easy way to convert a column to another type in this scenario?  What's the likelihood of Report filters following the same format as spreadsheet filters to include their own checklist of items within a particular column?