ADFS : I want to see the SAML data

There are a number of ways to see the SAML data.

Fiddler is one way.

You can use the TextWizard to URL decode and SAML decode. Refer my update on this - SAML : Encoding / decoding a trace

Refer Using Fiddler to trace a SAML IDP Request from ADFS 2.0

Dominick Baier wrote a Fiddler Inspector for Federation Messages.

Also described here : Viewing SAML/Federation response in Fiddler.

Also, the Troubleshooting WS-Federation and SAML2 Protocol tool. 

There's also the Feide SAML 2.0 Debugger.

And a URL Decoder/Encoder.

And another SAML 2.0 debugger.

But my favourite way is to use the:

SAML Tracer

which is a FireFox add-on..

Or Auth0 SAML tool

Or the Chrome SAML extension:

SAML Chrome extension 

And there are some more tools here:

Collection of Useful SAML Tools

Enjoy!