Re: Why Krishna did not participate in M.B war?
Adding my thoughts (based on what I read).
For the question, "Why Sri Krishna did not stop the war in the first place by making the Pandavas win the game of dice, he being the almighty?" --
The answer was offered (as per the holy book of MB) that Sri Krishna replied so to Uddhava, "Duryodhana, at the turn of events leading to the war, was solicited to play the game of dice, he said, his uncle Shakuni will play it on his behalf. Whereas, when Yudhishtira was solicited, he never said that I (Sri Krishna) will play on his/their behalf. If he had done so, I would have helped them win the game of dice in the first place".
The above answer is to show that everyone is bound by his/her karma and while the almighty can *ease* our earthly stay, he cannot play it for us, as then we will not learn our lessons.
Just some views, may not be the best answer, ignore if the answer is not what you are looking for.
jai hanuman gyan gun sagar jai kapis tihu lok ujagar