Your english is very bad. Nowhere it is written that Graeme Hick is a great batsmen. It is written Graeme Hick was a one day specialist. He averaged 37.33 scoring 3846 runs in 120 ODIs with 5 hundreds and and in 65 tests he averaged 31.32 scoring 3383 runs with 6 hundreds. So surely he was more of a one day specialist.
Test Cricket is the real thing. A bowler doesnt have limitations. One day is a batsmen's game. A bowler cannot bowl more than 10 overs, he has to bowl in fielding restrictions, he cannot try to swing the ball as much as he would love to as it might be called a wide. Till 2000 a bowler couldnt even bowl a bounce only after the year 2000 did ICC allowed bowlers to use one bouncer per over. Apart from that a bowler cannot test a batsmen by bowling around the rib cage area, cause even the slightest movement would cause the bowl to fly down the leg side and it would be a wide. With so many restrictions the batsmen already have a upper hand.
The real test of a cricketer is a 5 day match and that is why it is called TEST match, it tests the attitude, the talent, the patience, the courage and the mental strength of a cricketer. When you look at Ganguly's test record, you clearly find that his average of 40 overall is due to the fact he scored well against Bangladesh, Zimbabwe in subcontinent pitches. Even NZ is no match on subcontinent's pitches. NZ last won a test match in India way back in 1989 when Richard Hadlee was in their squad. Sri Lanka never produced good fast bowlers and lesser said of England of the 90s the better. This leaves Australia, Pakistan, South Africa and West Indies, these teams produced great fast bowlers and ganguly never scored a single hundred against any one of them. His sole 100 against Australia came against the weakest Australian bowling attack in 10 years since 1995 to 2005.
Just imagine, if you remove Bangladesh's average from Ganguly's overall average of 40, his overall average falls belows 40. Majority of his runs at a good average have come either on flat, dead batting tracks of India against NZ, Zimbabwe, Sri Lanka and Bangladesh or against Eng.
A batsmen who averages around 30 in test cricket world over except Sri Lanka, Bangladesh and England cannot be termed as great.