A direct ATEM driver will be extremely hard to implement. There are a number of issues…
1. No official protocol – Blackmagic do not publish the lowlevel ATEM protocol. A high level SDK is available but this would need a different approach to interface into V Control.
2. Control protocol needs constant command responses – if you don’t ack the incoming packets you get disconnected. If you do too many reconnection requests then you can completely lockup the switcher requiring a hard reboot.
The best way forward may be to use Skaarhoj’s ATEM Proxy to interface with the ATEM https://www.youtube.com/watch?v=4ZRxIBr6DSI this would provide a degree of robustness that directly connecting to the ATEM cannot.
If the ATEM is central to your production then you might want to look at JustMacros (commercial software with a free version) it is somewhat similar to V-Control but with direct support of the ATEM.