Things get tricky and sketchy when people start using that word, "supposed." The movies are what they are and the characters were portrayed the way they were. The prequels weren't "supposed" to be crap, but… Oh well.
Should-haves, could-haves aren't going to change any of the movies.
Boba was just a notch above a nameless character and I think most people agree that Lucas and everyone else involved with the movies could have fleshed out some of the B characters a little more instead of spending so much time filling every scene with so many essentially nameless throw-aways. For people into the books, video games and the rest of the expanded universe, there's probably additional depth to many characters that others don't see. I'm a huge Star Wars fan, but I draw the line at following stories outside the movies. That's just not SW to me. Could they make a movie around Fett? Sure, anything's possible. I think the success of such a picture would rely on how well the next movie(s) reinvigorate the franchise. At the moment, I don't' think a Fett movie would fly - in fact I'd wager it would be a flop.