The reason the dynamic datasources was taken out is that CFMX uses JDBC now instead of ODBC and JDBC doesn't have that capability.
Here's my opinion on commercial tags - I've never had the need to purchase one, but if I did, I would make sure that either the source code was readily available or at least modifiable. I stay away from encrypted tags, since I have no idea where this vendor is coming from and where they will be in the next 6 months. I'd rather develop it myself or hire someone to develop it to ensure code stability. Chances are someone else will have to maintain the code in the future and not myself. I need to leave behind clean readable code. There are de-cryptors available if push comes to shove.
Before I would upgrade my server, anyway, I would have contacted the vendor of that script and made sure it worked on the new version of CF. I would have done this with any other program installed on the server and had a test server setup and QA'd the whole thing, especially if I relied on those tags.