The Mahabharata Research
In the ancient Epic
Bhishma is one of the most charismatic characters in Mahabharata, and is renowned for the sacrifice he did for the happiness of his father, and sympathized for the agony he went trhough in his life to honour his vow.
The crown prince of Kuru dynasty would never have imagined the fate that awaits him, when he made the great vow to give up his kingdom and remain a loyal bachelor servant to the king. The royal lineage went through a series of tragedies which finally ended in the Mahabharata war. His heroics occupy a good part of Adi parva. And the epic sets aside a complete Parva to describe the battle during his tenure as the general of Kauravas. But Bhishma's role is not just restricted to these 2 sections in the epic. He stays throughout the epic, and was witness and party to almost all significant events in the epic. He was the backbone of the Kuru dynasty and was the most respected person in the Kuru kingdon.
Bhishma also had not lost any battle until he finally fell on the 10th day of the Mahabharata war, shot down by his own great grandson (of course that statement is debatable). Ahead of the war, Bhishma was rated by both the sides as the most powerful warrior on both sides.
Behind the Hero
Bhishma is a character who is remembered not only for his valour on the battlefield, but also for this principles and sacrifices. But hidden behind the much appreciated principles and values of Bhishma are his mere lack of more important values. Of course, life was not so easy for him, but the troubles he faced were indeed a result of his own actions.
It is a set of complex emotions that Bhishma encountered throughout his lifetime. Though he's honoured as the great grandsire, he emerges in my view as one of those immature perons who stuck literally to his promises and decisions without paying a rational thought behind the actions. Like a few other characters in the epic, Bhima found himself bound by a complex vow he made to please his step mother. And everytime he became a witness to injustice by the royal lineage or at times was himself forced to do injustice to someone, he was torn between the dilemma of breaking his vow or simply accept the flow. He chose to stay by the vow, and is indeed respected even today for this constat behavior in this regard. Had he known how to be political enough to make the right decisions and at the same time keep his promises, he would have been greater, but would have denied us the chance to read such a great epic, for the great war would not have happened at all.
The unfortunate choices:
Bhishma is in fact an example of how bad decisions could bring one down, or how picking the bad choice could ruin someone. He was unfortunate to have encountered some of the toughest choices once could come across in life. And Bhishmas's choices actually shaped up the epic as we know today. In fact he is solely responsible for many of the unfortunate incidents in the epic (not just his life). He made a great vow, which in hindsight was a pretty bad decision. But no one could blame him for that since his intention was good. But he's solely to be blames for the series of choices that he made then to abide by the vow.
He was torn between duty and love. He had to choose between self-inflicted responsibilites and most desired justice. Many a time, he knew that he was making a bad decision, but he saw consolation in the illusion that his deeds were justified by the way it enabled adherence to his vow. While abducting the princesses of Kashi for his step brother , he justified himself that it's the order of his step mother Satyavati. When he did a somewhat similar feat at the Gandhara kingdom, he believed it was for the welfare of his father's lineage. While tolerating multiple injustices done by the Kauravas, he found consolation in the thought that he's a mere servant of the king. Even during the game of dice, he was a silent observer to the atrocities done to Draupadi and he reasoned it to his age old vow to stand by the king and protect Satyavati's lineage as long as he's alive. Had he realized that rules and values are formed by humans and are meant to be re-written, the entire epic would not have materialized.
In Modern versions:
As much as in the epic, Bhishma is still seen as the most profilic character in Mahabharata. All modern day renditions of Mahabharata give utmost respect and importance to Bhishma. He is still depicted as the invincible warrior who stood between Pandavas and Victory. The manner in which Bhishma was brought down is still seen by the critics of the Pandava side as the first violation of rules in the war. But in fact, there wasn't any wrong doing on the Pandava side and no rules were discarded, since it was Bhishma himself who hesitated to defend himself when Shikhandi was before him. In many modern versions of Mahabharata, the miseries that Bhishma encountered during his lifetime is presented with a decent level of empathy that he stays as one of the most sympathized characters beside Karna.