Accurate string bends and vibrato don't come from your hands but from your ears. They can't be practiced mechanically like alternate picking and sweeping. It takes a more careful approach to develop your ear to hear pitch. I've heard many players who can play extremely fast, accurate scales and licks but can't execute a simple string bend and stay in tune.
Although I "discovered" Roy Buchanan when I was a blues-loving kid in the mid-'80s, the guitarist's first brush with something resembling fame came in 1971, when a documentary, The Best Unknown Guitarist in the World, aired on public TV. The documentary was about Buchanan, a blues-rock virtuoso whose gritty, distinctive technique inspired scores of guitarists, including Jeff Beck.