Friends, i'm new to this forum. But let me tell u one thing. Not only lord shiv has given boon to Draupadi in previous birth (daughter of kasi naresh), there is also other reason for having 5 husbands for her. Previous birth to Kasi Naresh's daughter, She was Indrasena, wife of Sage Moudgalya. He is very much ill and highly aggressive. Still Indrasena treat her husband as God and worshipped him dedicatedly. He was very much pleased and asks her for a boon. She asks him that he shud take 5 charming personalities, alike and I should spend time with you in beautiful places of this world (Friends, a woman can express her desire to her husband which is not sin). She had a very good time with her husband in 5 different personalities.
In the next birth, not married for long time, she prayed for Lord Siva. Whatever the boon she got from him, at first she was not happy and told that she doesn't want that boon. He promised that she will remain very pure.
Although Pandavas were born with the blessings of Lord Yama, Vayu, Indra, Ashwini Kumar, they were considered as Lord Indra only. Swarga Lakshmi is Draupadi. Those 5 Pandavas were the form of Lord Indra in previous Yugas.
Please don't show in such a way that Draupadi has no other choice than marrying 5 men and Pandavas are guilty for it.
When it was shown that Ved Vyas is happy with it, why Lord Krishna is shown having a sad mark on his face?
If Pandavas have done adharm in any way, then Lord Krishna will never offer his blessings to them.