I wonder if a million people marching in the capital, all holding the same banners while protesting would send more of a message of solidarity and unity to the establishment than the multitude of individual messages that at times can seem like personal advertisements for one's own creative genius.
What message does having the same slogan on every banner send to a government? After reading an Adam Curtis article where he talked about how in the US when people began to protest at the news of Donald Trump's presidency, they were holding banners saying "NOT MY PRESIDENT". Similarly in the UK, when we protested against our part in the invasion of Iraq the slogan on ready-made banners and placards read "NOT IN MY NAME". Curtis noticed how in the West, even when we are protesting, the individualism that drives capitalism is ever-present.
Curtis' example isn't exactly analogous to the observation I made above, but looking at recent trends in protests in the UK and US I do see some parallels. Many of the banners I saw were able to marry creativity and humour with a powerful message and really hit home, while others seemed more preoccupied with wanting to incorporate a popular phrase or saying at the expense of articulating the reason why they were protesting.