There's no sense in beating around the bush, let's just call it what it is: A shuffle. My usual running stride is a hip swivel from foot to foot, barely bending the knees. It's downright ugly. I've taken an interest lately in improving my form, to prevent injuries and get faster for "free". I suspect the pelvic stress fracture I suffered several years ago was due to poor form while I was in the middle of a rather tough (for me) training cycle.
There are lots of benefits to improving form, including: fewer injuries, better running economy, improved speed, and you look downright sexy.
But don't take my word for it, here's a few words from Sage Canaday:
It should not come as a surprise to anybody, least of all me, that Sage Canaday's advice is spot on. But it still came as a shock to me that once I began to do form drills and concentrating on maintaining good form on some of my runs, that running became nearly effortless.
For instance, on a recent training run, I ran the first 4 miles at my natural "easy" pace without thinking about how I was moving. The next 4 miles, I concentrated on bending my knees and keeping light on my feet. The result was astounding. With only a slight increase in heart rate (2 bpm, which is negligible) I sped up by 30 seconds per mile! One thing to keep in mind though, is that running with proper form uses different muscles than I'm used to, so I probably wouldn't be able to keep it up for anything longer than a 10k. But it's definitely a start. It's a little bit like starting from zero again, except that the gains will come really quick; the cardio is still there, it's just the muscles are being used in an unfamiliar way.
Your results will definitely vary, as no two people have the same (bad) stride. In fact, I believe that my improvement just goes to show how much form matters, and it's something that nobody should ignore.