Make him a true/chaotic-neutral guy working for the bad guys, without the redemptive arc. A nega Han Solo.
...
Fans and critics will have a field day deciding if he's an antihero or villain.
Something like this.
Actually, I always figured that Boba Fett should be approached similarly to BT's Bounty Hunter, and what Wayne was going for with Batman, what Tony managed (in the comics for a while) with Iron man, is merely a suit worn by any number of individuals over a period of time.
Add to that the Clones from the Clone wars, I could see any that managed to survive going into bounty hunting as a different form of war. This fits Fett pretty well - He's almost like the Punisher of Star Wars. So, maybe a cadre of clones take up bounty hunting and decide to wear a suit, and pass it from one clone to the next. People think he's unkillable, but he's like IG-88.
As a kid, I liked the look of the armor, and I didn't care for the way he was 'offed'. I enjoyed when the clone army got the same helmet treatment.
I always wanted to see the character handled in a fairer manner than what he got in the movies. As a kid, I immediately imagined that he managed to crawl out of the sarlacc later on, even before they made a book about the event.
On a side note:
I will admit that the EU made a few mistakes, especially in the handling of some the Characters seen in the movies. The direction of Fett, as well as the Solo/Skywalker families was, I think, a repercussion of the idea that those were the only characters worth writing about. The Star Wars Galaxy is a Galaxy, with room for lots of new characters and worlds. That's what the EU, in my opinion, should have shown off.
Lots of Bounty Hunters, pirates, Imperials, Republicans, so on and so forth to make the universe bigger.
They're kinda there with some of the new movies, but not quite.