The years of Umar left a long-lasting effect in the hearts of Muslims for the rest of history. The most dangerous thing is for the Islamists to be loved by the people before they get to power and then hated afterward. The third comment deals with civil society. The Islamic movement should be keen on developing and strengthening civil society even after the state is established. Even the Islamic state doesn't have control over everything under it.
Government is a small part of the institutions of civil society.
It is there to support and strengthen society. There must be more institutions of civil society, enough so that the people don't need the state. The Islamic movement must return power to the society through grassroots institutions. These institutions must be led by elected officials. There shouldn't be institutions exclusively for Islamists.