If death penalty succeeded in ONLY targeting the guilty heinous and serious criminals who "deserve" it?

Would many people STILL be against it as those for reasons that sometimes, innocents can be executed or something else wrong can happen, or would most if not all outright support it?

And who would be RIGHT here?

Or would most people, including civilized and intelligent ones, and for the right reasons, still perhaps be against it?

As in - maybe even those folks may not deserve or may not always deserve it?

Basically, in a perhaps still imperfect, but much more ideal and civilized world, with death penalty only succeeding in targeting and being used at officially guilty and serious criminals, how would most of us look at the system? Would there still be folks, and for RIGHT reasons, who would think it is too much or that it is barbaric, hypocritical and whatever? Thanks!