I just created test data from http://generatedata.com (see below) and tested against the master branch of both Drupal and WordPress. I could not replicate this issue.
Excel has inexcusably poor CSV parsing code - presumably because they have little interest in interoperability. I suspect the issue is with the data rather than the import code.
I suggest downloading and installing a copy of LibreOffice, which is free. Open your CSV there, and check to see if the formatting is correct.
If the formatting is correct, save a COPY of the CSV and try importing that to CiviCRM. If that works (and I expect it will), you can open up the two CSVs side-by-side in a regular text editor (e.g. Notepad, Sublime Text). The difference in how Excel and LibreOffice saved the file should hopefully be obvious.
If the formatting is wrong, that's a good indication that it's Excel that's generated bad formatting. In that case, open the Excel file in LibreOffice and save as a CSV from there.
Here's a snippet of the data I was able to successfully import. You can test to see that CiviCRM is working with semi-colon imports by saving this to a file: