I've always liked Alistor Smythe and his story. I'd be perfectly happy to see him build a spider-slaying robot, perhaps something like the robot from the opening of Tombraider:
I don't get why some people are so opposed to this idea. Seeing Spidey slow or halt the movement of a hydraulic mechanism with his bare hands was always a cool sight IMO. Imagine seeing him weaken the thing, climb on its' back, tear a basketball sized cpu/powercore out of its' 'body' and holding it victoriously above his head, sparks and wires flying about as it collapses to the ground. BAD ASS.
Now on the other hand, reducing scorpion and Rhino to mere robots created by Smythe is a TERRIBLE IDEA. Needlessly mashing multiple complex stories together into one half-assed oversimplified one. Can't we have some villains just exist with no prior connection to spidey? Having every villain come about directly because of spider-man is just lazy and worse, it makes spidey indirectly responsible for them, which cheapens his role as the hero. Costumed criminals are a dime a dozen in parkers world, they didn't just start showing up the day after he becomes Spider-man.