I just found a workaround that at least allows me to export and open dynamic spreadsheets directly from CRM as well as double clicking on them.
I picked on of the files that had the IE icon and right clicked on it.
Selected Open With...
Selected Choose default program....
Selected More Options (at the bottom)
Select Look for More Apps on this PC
Navigated to C:\Program Files\Microsoft Office 15\root\office15
Selected excel.exe
Once I did this on one of the files, all files with the IE symbol next to it changed to Excel. When exporting from CRM, I get the option to Open or Save it (before I was only getting the option to Save). When I open it, I have to enable content and hit the Refresh from CRM. Not as easy as it was before, but at least it has gotten me to where I need to be.