Most of the character analysis i have come across online label Mrs Bennet as foolish, obsessive, etc. Don't you think she just wants what is best for her daughters?

Mrs. Bennet is a product of her times. Financially daughters were a huge liability. They didn't generate income and the father's name was not past on. Working in this context we can understand Mrs. Bennet's eagerness to see her daughters married well. Still Mrs. Bennet seems consumed with this at the expense of other things that might make her daughters happy. She also tends to be brash and on the vulgar side. Again I ask what can you reasonably expect? She was poor and married young to a man who didn't treat her the best.