I find the ride too busy already; adding roll stiffness would exacerbate that tendency, so I looked for lower spring rate ("softer") springs a few years ago, without success. I admit that I didn't look very hard. My RAV4 EV is driven mostly empty; occasionally, I will load up a few hundred pounds of materials, my pressure washer or generator (both ~300 lbs), fairly frequently I move small quantities of building supplies such as 2x6 lumber, but mostly its maximum payload isn't needed or wanted*, and I would gladly give up some of that for a less busy ride.
I find the cornering to be very stable, up to maybe 80 MPH, and then it's a bit frightening because the low CG is misleading. "Stable" doesn't imply a lack of body roll, though. It does roll quite a bit, but it's also more truck-like in construction (meaning only the high roofline and the taller glass associated with that) than a Sedan or something I'd expect to corner flatter. I like body roll as a communicator of how far I'm pushing traction; it's usually a good provider of feedback.
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* = A few months ago I picked up an inexpensive
HF Scooter Carrier and I've been using it to move a huge compost heap, one load per week -- it's a 70 mi. round-trip to a parent's home where I visit weekly for lunch, with take-out Chinese. The HF carrier is rated for 500 lbs, and surprisingly I've dragged a wet load of compost onto it weighing >300 lbs, with myself standing on it to drag it up the ramp, and that's pretty close to 600 lbs -- and I haven't broken it yet. I don't know that I'd try to put 500 lbs on it and actually drive anywhere, but it can take a static load OK.
I've made perhaps a dozen round-trips with it. 300+ lbs. cantilevered this far off the Class III receiver hitch is really taxing this short-wheelbase RAV4, but aside from dragging the carrier on every driveway slope, it's working out well. I'm definitely glad that the RAV4 EV has the manual headlight aiming option; my 2010 Sienna (LE trim) AWD doesn't have it, but my friend's 2010 (Limited trim) does, and it's one of only two up-trim options I wish I had on it.
(the optional side ramp isn't installed in the pics above, but I have recently installed it, and haven't manged to break it yet, either.)
This is the most taxing suspension load I have; by comparison, I move eight buckets of rock every week, but that's centered over the rear suspension and is hardly even noticeable.
Oh, and lightweight but bulky stuff like mom's old range, which I hauled to a friend's son's house two charge sessions away!
