They should have given him a harder edge, but I would have preferred him be more of a toned down Eddington. A principled counterpoint to Janeway's Federation dogma, only smart enough to know that the Federation and Maquis needed to work together.
Like season 2-3 Tom Zarek.
That's the way I would have done it. I expected Tom Paris to be the bad ass of the group. The prison scene in Caretaker when he's talking back, the life debt poking he gives Chakotay, and the quick promotion because he's the best (if not the only) pilot. By the last season he became a Delta Flyer/Captain Proton geek (basically where I would see myself in starfleet).