So far, this season of "Smallville" has been a marked improvement over the seventh season, and that has much to do with the consistency of the episodes. With the key relationships now settled, attention turns to the season arc, and the result is another strong and compelling episode.
Something is clearly wrong with Davis Bloome, and as we see by the end of the episode, something is driving him to kill people. Is he going after people who already have abilities, or are his victims more scattered in nature? This episode doesn't quite provide the full answer, and that's a good thing. The audience is trying to figure out the truth of the situation, how badly it could go for Clark, and how this will drive him towards his iconic Superman identity.
Davis' interest in Chloe is another sign that her healing ability might come into play on Jimmy's behalf. Davis is not the most stable individual in Metropolis, and if he sees Chloe as some kind of touchstone to his own humanity, he could try to get Jimmy out of the picture during a requisitely dramatic moment. Both Tess Mercer (and her growing band of super-villains) and David are relatively close to Clark's world, so they represent a logical bridge from his small-town insular thinking to the world-class hero.
And that development process is coming along quite nicely. The writers were intentionally "exposing" Clark and his heroic activities in Metropolis as a means of forcing the character to evaluate his choices and options. Having John Jones as a mentor is also a brilliant move, and very much in keeping with the character's role in previous seasons. Clark is learning on his own what examples like Oliver Queen should have taught him much earlier: secret identities are a way to keep focus.
Clark is also struggling with the other side to that coin as he lives out the vigilante style of life. Being a hero with a secret identity means taking matters into your own hands, even when that means bending the rules is the very process of enforcing morality. One of my main complaints in in previous seasons was Clark's lack of questionable choices. That was resolved somewhat in his treatment of the Lana/Lex relationship, where his hypocrisy was often notable, but this is a better demonstration of character development.
We also see Jimmy taking notice of the new "hero" in town, and trying to uncover his identity. This places more pressure on Clark to resolve how he wants to present himself to the world. I think the writers are going to have to be intelligent about how the whole Clark Kent vs. Superman identity question is handled, since the glasses motif is simply not going to work on its own anymore. But I also think this season has made the case, so far, that the new regime could find a way.