Yes and no.
He was evil for keeping the entire human race locked up and enslaved, but that was only because the anti-spiral showed him what happens when spiral energy runs rampant.
So, he was an evil dick, but he did it for all the right reasons.

Well intentioned extremist at worst. Plus he redeemed himself fully by the end and got not one but two badass deaths

That is a very valid point.
And he did make up with his daughter.
That gets him points in my books.

I remember choking up just a bit the first time I was watchingthe series when Nia addressed him as father even after everything he had done.

Agreed. But he most heart wrenching moment was ep8. You know what I mean.
It was the first anime to make me shed a tear. But it was not the last.
Clannad/After story. Angel Beats. Katawa Shoujou (Not an anime, but still.)
Those have taught me a vital lesson in life.
Love. Shit'll kill you.

I do know. Although personally I found the leader of the black siblings death to be sadder then the badass leader of team Gurren's. They were both really sad though. I might have to rewatch the show this weekend