Very few people requested this feature when it was an Ideas and there are workarounds discussed such as Sage 50 Accounts (2014) successful connection via ODBC . You could create a new idea for this topic if you like though.
M A Y A R O M A N O F F
Based on your question, I assume your Sage 100 is on Providex. With assistance from a Sage consultant and Tableau expert, you might be able to pull the data into Tableau (be sure to test with both Providex ODBC drivers: 32 and 64bit). If you're still having issues, feel free to call me (my cell is on the email I sent you this morning).
Keep in mind that getting Tableau to connect to your Sage 100 is one important step of your BI journey. But then you'll have to find the right tables, fields, link them, create your Tableau data sources, create reports, validate them, and finally push them to the business users. And eventually you might want to blend your Sage data with other data sources for a 360 view of your business.
When I hear people with similar problems as yours, I tend to think that they are in the BI crawling phase. It's exciting, and they'll have a ton of fun learning how to walk, run and fly!
Let me know if you're interested in learning how to fly in weeks...