I see no evidence in the text of the play to suggest that Shakespeare did not want us to judge Lady Macbeth severely. She does seem rather pathetic at the very end in her sleepwalking scene. She seems to be repenting her part in the murder of King Duncan. Otherwise she seems even more guilty than her husband. She goads him on into committing the murder when he tells her flatly that he doesn't want to go through with it.
We will proceed no further in this busiiness.
He hath honored me much of late, and I have bought
Golden opinions from all sorts of people,
Which would be worn now in their newest gloss,
Not cast aside so soon.
Was the hope drunk
Wherein you dressed yourself? Hath it slept since?
And wakes it now, to look so green and pale
At what it did so freely? From this time
Such I account thy love. Art thou afeard
To be the same in thine own act and valor
As thou art in desire? Wouldst thou have that
Which thou esteem'st the ornament of life
And live a coward in thine own esteem,
Letting "I dare not" wait upon "I would,"
Like the poor cat i' th' adage?
She has a genius for manipulating her husband. She knows he prides himself on having courage. She also knows that he wants her to love and respect him. Macbeth's "tragic flaw" seems to be, not that he is too ambitious, but that he does not have enough confidence in his own judgment. He allows himself to be guided by his wife against his will and against his better judgment. He also allows himself to be guided by the three witches.