Our flights for June, 2017 have changed and we now arrive in DUS from east coast US at 0800. We are scheduled to depart for our final destination (Venice) at around 1500 on the same day. Should we hang out in the airport, or try to go into Düsseldorf for a bit?

You must be in the airport at 14 00 latest.
You land at 8 00 - get bags, go through customs, find a lokcer. Say at 9 30 you are ready to go.
Taxi or train or whatever - my guess is you are in Dusseledorf around 10 am at the earliest. it leaves you 3 hours before going back.
I would do it.

Thanks for the response!

Yes though Dusselsorf on most visitors' wish lists it maybe should be - though sadly blitgzed during WW2 so modern it has been pieced back together rather deftly -really neat pedestrian shopping area and nice Rhine-side walks and the Alt Stadt-Olt Town by the river is kind of like Paris' Latin Quarter in the sheer number of indoor and outdoor cafes, beer gardens and restaurants.

Visit Konigsallee -the Ko- for one of Europe's most fashionable streets -fashion boutiques on par with Paris and Milan (they say)-anyway an elegant street with canal.

S-Bahn takes you from Flughafen to Mitte or city center in a few minutes.

So, Düsseldorf is an extremely cool and awesome place to visit, even for a short time ( what happened in my case).
If you re interested in modern art and especially modern architecture I highly recommend you to visit Rhein promenade and go along the beautiful seaside surrounded by incredible views. And also visiting TV tower, which isnt far away where you can enjoy the view over the city on top through the panorama windows.
And you should visit a limoscanner website which might also give you some tips. <a href=´´http://limoscanner.com/partners/´´target=´´_blank ´´>http://limoscanner.com/partners/</a>