One of the biggest problems Steam's User Review system had from the very beginning was its vulnerability to review bombing. Since its entirely automated there is simply no way for the system to tell if the vast amounts of negative reviews are due to a genuine flaw with the game, or because one of the developers did something incredibly daft on the side. The end result was a highly unreliable system, a system where you couldn't really judge whether the game itself was any good or not.
As you might imagine, there is no easy way to solve this problem. On one hand you have enjoyable games like Firewatch getting massive amounts of negative reviews due to the developer's actions outside of the game itself, and on the other you have a countless array of games that have either become completely broken, stopped getting updated, or implemented pay-to-win microtransactions. Thankfully, Valve has decided to handle this issue in the best way they possibly could - by presenting the buyer with as much information as possible!
If you're interested in all of the details, as well as all of the ideas Valve tried before settling on this one, you should definitely check the official blog as its quite an interesting tale. So what is the grand result of all of Valve's efforts? Simple, a histogram showing the positive to negative ratio of reviews over the entire lifetime of a game, along with the ability to click on any part of the histogram to get a sample of reviews from that time period.
This way its easy to spot temporary spikes in negative/positive reviews, investigate why exactly that spike occurred in the first place, and then decide whether you want to support the game or not. This is obviously not going to fix review bombing, but to be perfectly honest its not a problem that needs fixing. If players are unhappy with a game they have bought they should be able to voice their displeasure freely, and this is something the new system manages to keep intact. Hopefully we'll see similar changes in the future as well, more information is always welcome after all!