While I agree that one should be able to tow a trailer of any size and sort with out bars........with this said......
I've towed my now gone 26' 6500-7000 lbs trailer with out, just a WD and a dual cam behind two gm rigs with an 8600 ext cab 8' bed, and 9200 gvwr CC with an 8' bed. No bars vs WD bars only, side to side rocking with side winds of the trailer was greater with no bars, and the dual cam had less rocking that the WD only. I made sure I was balanced, nose ever so slightly down on trailer, usually 12-14% HW. While I had no issues towing with out, I will say slightly nicer with bars. But not a major deal breaker!
ALL my other trailers I tow with out bars. Again, no issues except when loaded incorrectly with weight balance etc.
Yes your 1500HD is a sheep in wolves clothing! A very good truck! If one was available today, I would buy one in a heartbeat!
Marty