It was recommended to me to switch from 800 pound bars to 600 pound bars by you know who on my 25 footer towed with a HD 1/2 ton GMC. I did the switch, and I noticed the bars bent more to transfer the same weight, and that was all. I feel like in that circumstance, I wasted time and money.
So I believe every situation needs to be evaluated on it's own merrit, and not just jump off making changes because some parts salesman says it's "a must". Additionally, I don't think you can go too far from wrong if you follow the hitch manufacturer's recommendations, not the salesman's at the RV store.
These hitches are designed by engineers to do a specific job, and those engineers know more about the product than most of us will ever know.
"To compel a man to subsidize with his taxes the propagation of ideas which he disbelieves and abhors is sinful and tyrannical."-- Thomas Jefferson