I disagree. I think teams are very worried about Andrea (have you ever heard Stan Van Gundy talk about trying to cover him? He literally insults his own players in the process) and the ones that aren't often get shredded as a result (see: Utah).
As already mentioned, Bosh only got doubled because of where he set up his offense -- some teams double the high post regardless of who's playing it because of its low-risk high-reward prospects. Not so with big's sitting on the 3-point line.
In terms of just straight player comparisons, while Bargnani doesn't have the first step and finishing ability that Bosh had, he's a much better shooter, with deeper range, which is significant in terms of match-up problems. And defensively, they both suck: Bosh is the better help defender; Bargs is the better man defender.
I realize this isn't completely on-topic, but in a way it's actually quite relevant. One way of answering the "will we make the playoffs?" question is by comparing ourselves to years past when we did, and any time that happens the underlying suggestion is that we might be in the same unfortunate position as those Bosh-era teams. In other words, are we just back at square 1? And I think the answer is a much more hopeful "No".
EDIT: I didn't really make that last pgh. clear. We're not just in a better position than the Bosh-era teams because Bargs is as good as Bosh was. We're in a better position (and the comparison is accordingly relevant) because this team isn't constructed AROUND Bargs -- a player who, like Bosh, simply isn't good enough to be built around.
I won't respond to all of your opinions however I will say whether it's man to man defence or help defence, Bosh is the better defender, period, between the two.