A) The fact that it was a "managable" target because of good bowlers is exactly why Bevan played at a slow strike rate without taking any risks which could have caused him to get out. The fact that he strikes at 80 in the first innings (which is pretty good for his era) when he doesn't know the target while averaging 52 proves that he can play aggressively when needed.
B) I can't believe how someone would even take this seriously. Obviously the required rate isn't gonna be the same from the beginning of the innings as opposed when Bevan comes out to bat as Australia has aggressive batsmen like Gilchrist, Hayden etc who usually give them an aggressive start in the beginning even if they get out and don't get big scores.
In fact how have we not mentioned the fact that an aggressive batsmen with a high SR is more likely to get out playing a rash shot. Like that stupid helicopter shot Dhoni tires to play. I don't know how many times I have seen him get out trying to play that shot when it was completely unnecessary. I'll bet that puts pressure on the remaining batsmen as well. Seem to remember quite clearly that even Ganguly was criticizing him just a year ago for doing that.
A. Not sure since when teams scoring at a run rate of 4.8 started to get termed as aggressive, but that is the run rate Bevan managed batting first. Most of the time, he came down the order remember. Even at no.6 position, where he batted for majority of his career, his SR was 80 only, which suggests he couldn't really up the accelerator. Such slow-go indeed helped boost his career average though. He stayed not out 22 times out of 58 innings at no.6.
Dhoni on the other hand never really cared about averages batting first, and that shows in his SR as well, 94. Batting at no.5-7, Dhoni averages 47 but with a SR of 92. And he didn't have not outs to boost his average, just 16 out of 72 completed innings. By contrast, Bevan averaged 52 at the same positions, but with a SR of 80 and had 33 not outs (out of 87 innings).
There is absolutely no comparison between effectiveness of Dhoni and Bevan batting first. Dhoni is miles ahead of Bevan. The only comparison is in their effectiveness as good chasers. But statistics suggest that is also in Dhoni's favor.
B. Precisely. But his almost complete lack of noteworthy performances in any run-rate wise tough chase (>275) shows that whereever he could not just rely on the illustrious top order to contribute and him to just knock the ball around and canter to a win, he invariably couldn't step up.
Regarding helicopter shot, please show me instances of how many times he threw his wicket away playing that. I suspect barring circumstances where he HAD to throw his bat around (the death overs batting first) I don't recollect him getting out playing that ever.