Then give me open protocols and endpoints so that I can write C# code to talk to it.
There is one, it is called http or https. I agree that more direct interfaces would be nice, but there are currently methods of controlling and passing data to a PHP server from any language you can open a port in.
It takes a lot more that just http. I'd need to know the URL schema if you're restful, or the method names if you're SOAPy. Then there's the format of the data (SOAP, JSON, XML ..) and the expected data fields in the data sent and received, etc.
I don't think it's fully implemented yet, but here's the protocol Appleseed is using:
http://svn.appleseedproject.org/trunk/_documentation/quickso...
From the source, it looks like they're building abstracted PHP libraries, too. And it's an event/hook architecture, so you can pop this protocol out and put another one in, theoretically.
I don't know if this is a placeholder protocol while they build the software, or if this is what they plan on using and evolving.
I've seen BASIC used to power million dollar companies.
To throw out some project simply because it is built in a language you don't like is counter-productive. I know PHP is the language to hate around here but you could do a lot worse in a web environment.
PHP really is the new 'BASIC', it has a very low barrier to get started and that's why plenty of people associate it with crummy code but you don't have to write crummy code in any language.