Import of values from CSV will match on an existing column, so there will not be duplication of objects. As far as workflow, it would be: Export->Filter in Excel->Save Sheet->Import same sheet into CPE.
We're certainly not done improving the CPE, and in future ports of Win32 functionality to the web, we will strive to leave the legacy applications in place for those that are used to them. In the case of CPE, there were some larger technical hurdles that prevented peaceful co-existence.