This question came up in our open question Insight session a couple of weeks ago. The solution is to remove any conditional formatting you have in the view. When a measure has conditional formatting on it Stratum creates a set of merged excel columns so that the formatting can be included. If you remove the conditional format this will not happen, making the data in the column easier to use in excel.
Also – coming up in the next release – 6.9 – if you have a license to the Stratum Broadcast Server you will have multiple options for exporting to excel. One will be the same export available today – which is called an Excel Report. The new format is called Excel Data which will be exported with all the formatting removed, the values repeated on each row and no totals. By doing this Stratum is able to export large data sets much faster. The idea behind this new feature is to allow for exports that are made for information delivery, which are the Excel Reports that you can export today. The new Excel Data export allows for exporting data to be used as data in a pivot or other situation where a large amount of raw data is required. Other examples would be for exports to Power BI or to a table in excel.