He hid in the trash after the Imperial fleet left Hoth, figuring that Han would do something similar, and then followed him to Bespin. I guess that might not be impressive in terms of fighting, or talking, or whatever, but it's pretty crucial to the plot, and it shows that he's incredibly competent and not someone you want looking for you. And it did happen on screen.
It is, and it was one of the things that I picked up on, when I saw ESB in the late 80's. (I was late to the SW party, what can I say?)
Yeah, being beaten by a flailing blind guy with a stick doesn't do much to build your badass combat cred.
This pissed me off in ROTJ. Such a cool character removed from the movie.
In the old WEG RPG books, they brought out a Bounty Hunter book, detailing all sorts of things about the rules and life style, and in one of the little short story blurbs they recemented the badassness of Mr. Fett. It went something like this, and told by adjunct or aide:
Boba Fett walks into a Moff's office dragging a bloody and bleeding body of a space pirate (I think) and demands the bounty of a million credits. The Moff blusters about how the body is ruining his carpet and how this pirate isn't worth that much.
Boba pulls out a Thermal Detonator, and activates, placing it on the desk. Then says, "Two Million."
Again, the Moff tries to bluster his way out of it, but everyone, except the Bounty Hunter is too scared to do anything. Boba counters with, "Four million."
By now the little green light on the most dangerous explosive in the SW has changed from a slow pulsing to a slightly faster yellow, and everyone is watching, waiting, terrified that it'll change from yellow to red, seconds before they're all blown up. The Moff finally breaks and gives Boba the 4 million credits he demanded, who then picks up the detonator, casually switches it off and walks out. The body left behind in the office.
The Moff's Aide who was recanting this story, immediately requested a transfer to a battle cruiser, because getting shot at in space was safer than having to deal with Fett again.