The only functional reason to change bars is to get the pullback where it needs to be for you. Why? An illustration: place your hand flat on a table and flex the wrist from side to side. Not much rotation is possible, and the range of comfortable movement is about half of that. Pullback affects this range of motion. If while holding the bars you have to rotate you arms in or out to get comfortable a long ride will prove very tiring simply due to the arm and back muscles working to keep your wrists straight, resulting in aches in your back and neck which in the long term can become chronic. Personally I kept the stock bars for too long and lived with the excessive pullback which is, as stated earlier in this thread, angled too far back for the seat position for me. I will never assume it's universally wrong nor perfect for all -- an impossibility either way.
Any other parameter is to tailor the bars to a specific use such as canyon carving / touring / errands / whatever else, and any combination, and are in the realm of getting comfortable on the bike. As such, there is no reason to live with bars you are not comfortable with.
This is why I made the prototype for TharBars. See this thread: https://www.wristtwisters.com/forums/...eap-13145.html
Not surprisingly, once I got it adjusted properly it never got moved again, meaning a fixed bar would work as well. The question then is which bar? It's strictly a hit or miss proposition as even given a recommendation from someone who rides the same bike as you and is the same stature, their bars may not work for you for a variety of reasons.
On the subject of the necessity or desirability for "leverage" in steering inputs -- I have always run widths most others deem anything from "weird" (my favorite compliment!) to unsafe, and all I can say on that subject is "It works for me.", never assuming it will for anyone on the planet. As LDH stated wider bars can be a detriment to accurate control inputs: leverage works both ways, being easier to steer (as if any motorcycle is difficult!) and reacting to every twitch and sneeze. Most tank slappers I have witnessed were the result of overcontrolling once the oscillation starts, and with lots of leverage every "correction" simply feeds back more out of phase forces, exaserbating the oscillation to the point of uncontrollability. The narrow bars I run take a tiny amount more force to initiate a turn, but combined with appropriate body english amounts to less effort spent, gives plenty of feedback, and isn't prone to unexpected jumps in response to moving in the saddle: a big plus when railing a twisty road. Again, for me. Another thread on this subject: https://www.wristtwisters.com/forums/...nge-21152.html
Pretty well sums it up.
On vibration: never expect changing bars to make much of a difference in vibration levels. Some may work on one bike and not on another outwardly identical bike. One thing that does work quite well is to keep as light a touch on the bars as possible. The less you grip the less vibes you will feel. This, of course, requires the bars be placed such that they are not being used to support more than the weight of your arms, yes even when braking. Again, works for me.