Jeremiah's popup exceeded the van's hitch weight limit by a substantial amount, so the result is not surprising. Towing within the tug's specified limits, or a bit over the limit with accompanying hardware (i.e., a custom receiver to spread the load over more of the unibody), should yield a different result.
Vans are better at maneuvering than more top-heavy full size pickups and trucks. They have a pretty long wheelbase, good for stable towing. With brakes on the trailer, they stop fine, too. They can do a great job of towing. They won't, however, tow nearly as much as a larger vehicle.
I like some of what Can-Am does, but I don't know exactly how far they push the envelope. If they were to say that a minivan can be set up to tow a 28', 5000 lb TT with 700 lbs of tongue weight, I'd say no thanks (I don't know if they would do this, it's just a for-instance).