[DemolitionRed]

By 'visionary' you mean 'future thinker' and so regardless of the damage she did and the future she created, yes, she was a visionary, but keep in mind Starlin, Hitler and Mussolini were also visionaries. What Thatcher did was pave the way for neoliberalism. Neoliberalism was certainly Thatchers future vision, though I somehow doubt she wanted it to go quite this far... perhaps I'm wrong.

As for the coal industry, she didn't destroy it because coal is a dirty fuel. Good grief, once we'd closed down the mines we started importing coal from overseas! She closed most of the pits or sold them on to private investors because they were not economically viable. Harold Wilsons government closed more pits than she did. The problem with Thatcher was, she supported and encouraged police brutality on picketing miners. She wreaked havoc on long-established communities and that will never be forgotten in pit land north.
She heavily demonized and rallied to destroy unions because unions spoke for the working man. She openly described both the union and the miners as 'enemies within our nation' and her propaganda machine was so good, the older generation today still curse British unions! Thatcher created the most bitter industrial dispute in British history.

There are many unforgivable things Thatcher did but a few that come to mind are: She promoted and brought about a new act against homosexuality which resulted in resentment and distrust of the LGBT community (something Cameron apologized for in 2009) and she did this under the guise of, "we must protect our children.

She openly supported human right abusers like Augusto Pinochet and the South African apartheid.

She divided ethnic minorities which brought about the Brixton riots.

She was actually quite a brutal woman.