Dear Erik,
Thank you for your very valid query.
Apparently, you have not read all the stuff The Building Coder has to say on this topic:
http://thebuildingcoder.typepad.com/blog/about-the-author.html#5.28b
What you are doing is technically possible, and in an uncertain space as far as the official license is concerned.
If you are running Revit as a server just to read information from the BIM, there are probably better ways to go already now, either extracting the information you are after yourself and storing it in an external database, or making use of Forge:
https://autodesk-forge.github.io
If you wish to modify the BIM via an externally accessible service, your safest bet will be to talk with the people responsible for the Forge design automation API and Revit I/O and let them know your needs. Look what it can do for AutoCAD DWG today:
https://developer.autodesk.com/en/docs/design-automation/v2/overview
What exactly do you wish to achieve with your service?
What timeframe are you thinking of?
I hope this helps.
Best regards,
Jeremy