Fusion has a newly designed REST API. It's a better model than current one which is heavily related to vmrun, in terms of

• REST API is the new standard way to control fusion in future, with official support. While vmrun is gradually going to end of life mode
• It's easier to consume as a client
• Current vmrun approach has a lot of hacks, especially those around IP address parsing. Those are not needed when it's officially supported in REST API.

The only problem now is the REST API is only supported in Fusion. However, it's going to be supported in future version of workstation too, and it's fully compatible.