I noticed the same thing on my 2010 van. I complained to the dealer...., and got the inevitable, "They all do that. There is no adjustment or way to tighten it." I looked under the dash and checked every bolt I could find, but all seemed tight, so I lived with it until I got another van.
I noticed an improvement on my 2011 and 2013 vans, but there is still some side to side free-play. I don't think that would fly at any of the Japanese manufacturers, but it didn't seem to be a high priority to Chrysler. It will be interesting to see if there is an improvement in the sixth generation vans.
I park the pedal assembly at the bottom of it's travel (2014 DGC), using the adjuster motor to wedge a wood block behind the assembly and against the firewall. This firms up side-to-side wobble as much as possible, but obviously only in the fully extended position.