Well, contracts are so easy to re-sign. If he continues like this through the whole season and proves he is consistant performer and if he proves he is indispensable to the club, he can get an improved contract again. He can moan again and get a better contract, too.
No, seriously, why does it bother you that he doesn´t have a multi-million contract? Isn´t it better to save some much needed money on contracts? Sure, the boy deserves better than Boumsong but if he loves Juve (which I think he does) he is not interested only in money. He is still young and to be honest he is not a superstar yet to get such a wealthy contract. We should be happy with the fact that he want to prolong his stay here to play a role in our defense for years to come.
I say, keep the contracts as smaller as you can because it will repay to Juve. Better than thowing money around and eventually go bankrupt.