It's possible to be quiet and stoic and still strong and interesting. Chakotay could have been a great character, if they hadn't made him so laid-back and a yes man. Even in those episodes where he actually stands up to Janeway, he is never ready to follow it through - as in "Equinox", when he says he would have been "out of line" to mutiny against Janeway. For crying out loud, this guy was a Maquis leader! Did the writers just forget about that? He resigned from Starfleet to join a terrorist group in order to fight for what he thought was right. So why is he acting like a good, obedient Starfleet officer? The character should have been a lot more intense and ready to stand up to the authority, he should have been an equal to Janeway - he had had 1/3 of the crew under his command (and yes, the Maquis should not have become good Starfleet officers by episode 3, or even by the end of season 1) - not her lapdog; they should have butted heads a lot in the first couple of seasons, but grew to respect each other (more like Adama and Roslin in BSG). And even in the later seasons, Chakotay should have been ready to really challenge Janeway when she was doing what he considered deeply wrong (as in Equinox), despite his respect and affection for the captain. That would have made the dynamic a lot more interesting.Right, I had sort of forgotten about the alleged lil' Chakotay, Jr. back in the Kazon days. Chakotay definitely deserves some respect for trying to do right by his kid.
It occurs to me that Chakotay probably has many other redeeming characteristics, especially the sort that have to do with being a nice guy and having good ethics and so forth. But Chakotay's a quiet sort of character to start with, and when he's in a scene with the outgoing Janeway (and Mulgrew's intense stage presence), nobody notices the quiet guy.
And of course, if you're going to refer to his background and include his spirituality/faith in his characterization - and there's nothing wrong with that in itself - find some writer who has a clue about Native American traditions and beliefs, and who won't make it a mess of New Age cliches.
Finally, I know that a few people here will disagree, but I don't think that Beltran had the right presence, and he was never really that good in the role, even before he started sleepwalking through it. I haven't seen him in anything else so I don't know if he's otherwise a good actor as some people say, but based on VOY, I was less than impressed.