Feynman diagrams, Riemannian geometry (General Relativity) did.
If you look at how most physicists use the gamma matrices, they are very reluctant to treat them as algebraic objects and rely heavily on their matrix representation. A proponent of GA would say this is like using the matrix
[ 0 1
[-1 0]
everywhere in your calculations instead of just using i and remembering that i^2 = -1. Sure, it's formally equivalent but you'd still miss out on a lot of the beauty of the complex numbers.For what it's worth, I have a soft spot in my heart from Geometric Algebra, but I think it still needs a lot of notational improvement before it'll ever see any real adoption.
If you're curious about GA as it currently stands, I'd check out Geometric Algebra for Physicists by Doran and Lasenby.
That said, nobody really knows about the future of twistors in physics. Twistors have some really interesting algebraic properties that may eventually get leveraged in a main-stream theory but they could also just end up being a mathematical curiosity that never has any real impact.
I think I feel pretty confident saying that twistors will never have the cultural / philosophical impact on physics that Feynman diagrams have had (for good or for ill).