I import PDF files into Illustrator every day from programs like AutoCAD & Revit, and every single time, it tells me that Illustrator can't read the text in the font Arial, and that it must substitute it. This turns it into squares that are all giberish. The only workaround is to outline text in Acrobat before importing. Please learn that people are using programs outside the Adobe environment (for which there is no substitute by Adobe) and we need these BASIC capabilities.