Here's a short video on arpeggios. I must admit that, when I first started taking lessons again a few years ago, the first thing my piano teacher did was to dispel the myth that one needs to be all wrist-twisty when playing arpeggios. My previous piano teachers had taught me to play them legato, which required a bit of awkward twisting of the wrist whenever the thumb goes under. For the past couple of years, I've been doing something like the small "leap" discussed in this video. The instructor here says that there will be a small pause during the leap, but I've found that practice makes the pause barely noticeable. Also, if I don't try to play them super-legato, the pause isn't noticeable at all.
All of the practicing has contributed to a legato sound in all of my arpeggios. It's not something I worked toward, but I've noticed that they're sounding much smoother and not as "jumpy."
Small goals. Little victories.