Q: Dictation does not fill in bar after listening

Assuming that you are referring to the loss of dictated text after pressing Done that's a bug in iOS 8.2.

To work-around the dictation loss in Safari rather than touch the Done button to end the dictation just touch the text field.

if the dictation is lost because Siri times out just shake the iPad to bring up Undo facility or press the .?123 key at the lower-left of the keyboard and touch the undo key

Report your Siri dictation bugs to Apple at http://www.apple.com/feedback/ipad.html

See below

1. Does the text appear on the screen and then disappear when you hit done?
2. Does the text not appear at all when you use dictation?

WIth thy reference to point number 1, there is a bug in iOS 8.2 where dictated text disappears if you hit the Done button. There are currently three workarounds.

Tap on the end of the text after you finish dictating and that will stop the dictation without deleting it.

If you already hit done and the text disappears, share the iPad to bring up the Undo button and tap that

The third way is to use the undo key on the keyboard. Tap the 123 key to get to the undo button.

WIth reference to point number 2, Is something blocking the microphone, like a cover or some debris?

A Note to JimHdk ... It took me quite a while to type my post because I got interrupted. I wouldn't have posted the same information that you just posted. My apologies.