I agree he may not of proven himself at Test level in all conditions yet but he has done a hell of a lot more then the other more seasoned batsman in the lineup the past year or so.
And he has scored one day 100s in different environments (West Indies, UAE, and South Africa twice).
And if you look at his stats at this stage compared to some other players, he's certainly around the mark to keep going, you gotta remember he takes wickets as well, I think sometimes people forget that.
Watson after 19 tests:
1 hundred
8 fifties
Avg: 39.50
Ponting after 19 tests:
2 Hundreds
7 fifties
Avg: 40.06
Langer after 19 tests:
2 Hundreds
7 fifties
Avg: 32.25
Katich after 19 tests:
2 Hundreds
7 fifties
Avg: 39.75
You cant deny the guy is a star and can certainly play, I'm sure in a few years you will certainly be convinced about him.