Microsoft Excel sheet names can only be 31 characters long. We don't have control over this. 

We ensure everything gets exported by prefixing the sheet names with numbers. If for example you had a survey with the question "Did the agent resolve... " the sheet name would be prefixed with a number e.g. "1. Did the agent resolve ...". 

You'll need to pay attention to the excel sheet if your campaign has two or more questions that essentially start the same text.