Bevan played for a strong team, and he surely didn't get enough opportunities to chase big totals. Given his test match stats, we have reasons to think that he may not have been a technically sound player - he averaged 29 after 18 tests. Though this is not a big sample, it is not a small sample either and his sub 30 average indicates that he was not technically better than Dhoni as a batsman.
His test record has nothing to do when we are talking about ODIs.
He surely has his weaknesses particularly against short balls, thats why he couldn't succeed in Tests.
But that didn't stopped him from being a gun ODI finisher.
Dhoni wasn't the best of test player himself.
Dhoni is a much superior ODI batsman. It is just not an issue of batting averages here. Bevan wasn't a big hitter of the ball, while Dhoni is a big hitter and can hits sixes and boundaries at will. Even accounting for the relatively easier batting conditions during Dhoni's time, Dhoni is still far more versatile compared to Bevan.
Yeah true. Bevan don't have range of shots like Dhoni.
But thats not all what matters. We have to see who achieved more as a batsman despite what they were capable of.
Bevan, again has his limitations, but he did found out ways to finish the games. Used to rely on strike rotation.
I watched his century against NewZealand, and he chased 7+ rpo in last 10 overs exclusively without any boundaries. Managed 100+ SR with for a century with only 28 runs coming off boundaries.
http://www.espncricinfo.com/ci/engine/match/65624.html
And Australia's top order, no matter how much dynamic it was, was susceptible to collapse due to their aggressive style of play.
So many times he has bailed them out.
In above match, he chased down 250 when Australia were 82/6.
And he could hit boundaries as well when needed as he did against WI when a boundary was required of last ball.
http://www.espncricinfo.com/ci/engine/match/65531.html
Even in above match, he chased 170+ when his team was 38/6.
And comebacks from such hopeless situations were unique in those days unlike today.
And as I said earlier, 230 used to be a par score those days, so SR in 70s is all that was needed to chase those totals, and thats what Bevan did.
There aren't many #5,6 even today with 50+ batting averages - infact Dhoni has the highest batting average at #5-#6 since 2000, and Dhoni has a much higher match sample compared to others who did well at these batting slots. The other batsmen who average 50 or thereabouts are top order bats. Dhoni is truly unique in the ODI world - he can average big, he can average big as a middle or lower-middle order bat, he can steer a tough chase, he can steer a tall chase, he can absorb pressure like nobody else can, he can hit 8-10 runs an over for a dozen overs if necessary.
The fact the atleast top oder batsman today can average in 50s while they couldn't do that in Bevan's time tell us something. Batting conditions have eased out a lot.
And btw AB averages in 80s at number 5 while Matthews averages 50+ at that position. Although in lesser matches but its not unique in this age.
And just like Dhoni, Bevan was successful at whatever number he played at.
As I said earlier, Dhoni the player is better than Bevan the player, but to say that for Dhoni the batsman, would be stretching too far.