Now, obviously the new guys the Mavs welcomed at the beginning of the season didn't pan out quite how we'd have liked them to. Darren Collison's shown himself to be more 'inexperienced and inconsistent' rather than 'young and exciting' and Elton Brand's shot went missing for long stretches and his age seems to have shown very starkly, but at least they've both shown some value to the team as a whole, with Collison showing the potential to be the first guard off the bench and Brand providing tough D and rebounding even when he couldn't make a shot to save his life.
(I'm going to excuse the rookies because, well, they're rookies. And besides Cunningham, who we've basically seen nothing of, there are positives to be had from the performances of Crowder and Sarge)
Kaman, however, seems to be only good at scoring, and he isn't even consistent with that. Also (and this is a big ALSO), if he plays well (i.e, scores a decent amount of points), it usually means it's at the expense of other players' shots, which becomes a huge issue when this means that Dirk doesn't get enough shots or even touches.
Dirk IS our best player, after all, and I think it's only right that the offense runs through him just about every single time down the court. His shot-making ability from just about anywhere on the court simply opens things so much more for the other guys on the court.
To even make Kaman effective, he needs to be fed the ball constantly. What if he makes shots? Good, but he's never going to be the one carrying us to a win in tight 4th quarters anyway, so what's the point? I'd rather feed Dirk constantly, even when he's on an off-night, simply because even on his worst nights he can still come up with a big shot/play down the stretch, and if he's having a good game, why not feed the hot hand?
And Kaman doesn't even make up for his offensive crimes by making a difference defensively. He's just not tough or athletic enough to. And anyway, as we've seen from 2011, Dirk works best with a athletic-defensive type of C (Haywood was defensive but not athletic, and he turned out not to be an ideal fit).
In other words, I think the Mavs need a C who earns his money on the defensive end, and if possible, can at least be a threat to finish around the rim, but that would just be bonus. If we do get any big men who are known more for what they can do offensively, they should be players who come off the bench, if only so the offense from our frontcourt doesn't drop off the map entirely when Dirk sits.
This team obviously has gaping holes in many areas, and solving the big men situation isn't going to magically vault the team to championship-contender status again, but it'd help tremendously I think. I know I haven't listed any suitable replacements, and my opinion is mostly based on the 'eye-test', but that's my two-cents worth.