I know a lot of people (myself included) are somewhat disappointed at how Imperials/First Order in the new canon are reduced to being simply pure, faceless evil; with the exception of one or two characters who actually have deeper, fuller emotions and motivations. We yearn for the EU days, when Imperials had their own families and dreams, and some were even conflicted about the Empire's methods. However, the more I think about it, the more I think this may have been a good decision on Disney's part, and is likely only temporary.
In making movies like these, you don't necessarily want the audience sympathizing with any of the bad guys (apart from the one or two you deliberately make sympathetic characters). You don't want people thinking of all the grunts being killed off as being misguided people who are honestly trying to make the galaxy better, nor their officers as people who recognize the methods as being wrong, but believe that the ends will justify the means, because the galaxy needs a strong government. In movies, where time is limited, such thoughts distract from the main action, and trying to portray them wouldn't be very believable without devoting even more time to it, further detracting from the primary story.
Even the original Star Wars trilogy was this way. In the entire trilogy, Darth Vader is the only villain who appears to have a real sympathetic side (finding out he's Luke's dad in ESB, then seeing his struggle in RotJ). Pretty much everyone else is either a very hate-able villain (e.g. Palpatine, Tarkin) or just cogs in the giant machine which is the Empire (e.g. Stormtroopers, Piett). It wasn't until the EU that the Empire was really given depth and complexity.
My prediction, then, is that the one-dimensional-ness of the current canon was implemented for the purpose of the movies. Once the movies are finished, we'll start seeing new EU adding more depth to the galaxy once more. (Also, I imagine this will simply start happening naturally as more novels are written and more authors get involved.)