Gandhi's appeasment politics towards Islamism and its end result Pakistan is well known.
His understanding of Hinduism was faulty. Gandhi's interpretation of Gita remains an exercise in futile duplicity.
Gandhi had a dictatorial mindset. He ensured that Subash Bose could not continue as Congress President despite his electoral victory by boycotting him and made Bose resign his presidency.
To cap it all, Gandhi's totalitarian stance overruling Congress Pradesh Committee Majority Members recommendation on Sardar Patel and coronating jawaharlal nehru was something whose deleterious effects and impact we are living even today.
Apologists have cited lot of reasons for this mistake, highlighting Nehru's younger age, Nehru's not accepting second position etc. as reasons for gandhi's wrong decision.
In a situation similar to India's Lincoln preferred a civil war to keep the union. Gandhi backed off against the Islamists.
Thanks to Lincoln US remained united and became a super power. Thanks to Gandhi and Nehru, India became a begging bowl case and got kicked by Mao and his PLA.
Despite brainwashing carried out by gandhiwallahs, history will not judge him kindly for his deleterious long term impact on Indian polity.