David, the answer is a definite maybe! You can do somethings with CAT that used to require DDUtil, such as have multiple comm ports that could talk CAT to Powersdr. Now you can define multiple CAT ports for a slice and do not really need DDUtil for that. However, I find so many aspects of DDUtil to be handy I would probably retain its usage since it provides a lot of power you might need in the near future and if you get it working now you will not need to worry about it later.
Prior to the 1.6.17 release of SSDR, CAT allowed definition of vcomm pairs, it called them shared ports, that you could use in DDUtil just like you use VSPMgr vcomm ports. Unfortunately, these caused more problems than they were worth so that feature no longer exists, so if you need shared comm port pairs, you need to retain usage of VSPMgr or whatever your choice was of vcomm port management tools.