In addition to Jeff's points, there's one other issue: There is no such thing as a uniform histogram. The histogram is a tool used to verify where your light and tonal levels are. As Julianne Kost puts it, a histogram is a display of "piles of pixels." If you have a high contrast image, your histogram will show a pile of pixels on the left and a pile of pixels on the right. Is this right? Is this wrong? The answer (or question) is, as Jeff says, '...does it look good?'. If you end up with a cool looking histogram but the image looks like $%*it, what good is it?
Back to the histogram indications: Pay attention to the left and right "walls" of the histogram. If you see these "piles of pixels" climbing up either, you've got problems in that you're underexposed to black (no detail) on the left, or overexposed (blown out) on the right. Fix those using Exposure and Recovery (for blowout) and Blacks & Fill Light for under exposure. In Develop, there are two clipping tools in the histogram display that you can access to help fix those issues. Hover over them to see your issues, or click on them to activate and show you what you're fixing as you fix it. When done, click on them to turn them off.
I use LR for 95% of image adjustments. Only when I have to swap heads, remove unwanted image elements or combine image elements (as a montage) do I port to PS for adjustments. A good practice is to only send uncropped, un-vignetted (full) images to Photoshop. You'll understand this once you send a cropped, vignetted image to PS and then wish you had the rest of the image to work with. And it sucks to start over.
Here's a tip to decide whether an image is "fixable." If blown out, run the exposure control all the way to the left. If you can see detail, you can work the image. If underexposed, run the exposure control to the right. If you see detail without too much noise, you can work that as well. If no details emerge, you certainly have considerable PS work ahead to "fix" the image. This is when it is good to select a better image.