WCF Weakness

WCF doesn't support the following requirement:

Bidirectional (Server <--> Client) + Stateful + .NET 2.0 Client App

Statefulness:
Whichever binding you use, you can achieve this by enabling the session for your WCF service.

Bidirectional:
Only when you use wsDualHttpBinding WCF supports Duplex Message Exchange Pattern. For this to work

• Your client must use .NET 3.0 and above
• You must enable Session so it's stateful as well

.NET 2.0 Client:

• When you use basicHttpBinding, your client can be in .NET 2.0.
• When you use webHttpBinding, your client can be in .NET 2.0 and call the WCF services using HttpWebRequest.

Alternative Option:
.NET Remoting supports all the above requirements.

My comments:

If you disagree with my conclusion, I would be happy to hear your thoughts about this.