Steam's reviews, much like the entire Greenlight system, have room for improvement. In addition to spam review bomb issues, there's also a ton of clutter with the current UI, though Valve has responded to one problem in particular this week -- recent reviews.
Now, Steam users will find that assessments in the last 30 days are more visible, to give people a better picture of what a game is like after its been fixed, updated, or content has been added. There's also a checkbox to disclose press copies. So yeah, baby steps, but it's something.
Customer Review System Updated To Show Recent Reviews And Summary [Steam]