I have really long legs and an average torso. My 6'2" build has the legs of someone who is 6'3" or 6'4". Thus, I ride a 59cm bike, which puts my handlebars very far forward. Ideally, I should have a bike with different geometry, but I've gone 5,000 miles on Bikeasaurus Rex and I'm used to him. So a handlebar bag wouldn't offer me the same access as a hip bag simply because I wouldn't be able to safely reach into it without looking.
I also love knowing where my passport and debit card are on and off the bike. It helps me keep track, as I am prone to losing things (Last tour, I lost a helmet, three straps for my hammock, a pair of sunglasses, and I had to backtrack 157 miles for a forgotten iPhone).
I try to keep bags off my handlebars anyways so I can take my hands off without losing control. I've got a tiny little front bag that I use for spare tubes, but when I tour again I will likely ditch that as well. On long stretches, it is divine doing a mile with your arms hanging and your back straight, just to loosen up the shoulders. Bike touring is a very subjective experience. Some people like the weight on their front wheel for balance, others use six separate bags to carry a house worth of gear. Some people carry nothing but a toothbrush and a credit card.
I have considered a bike-packing setup from Relevate Designs- I'd go there before I went for custom gear, unless the price was right. But the way I have it set up now, I have a Jandd frame bag strapped underneath my top tube and a pair of Ortliebs on my back rack, and I have toured without the Ortliebs, using a single dry-sack. I carry very little and don't need more bags.
I don't mean to deny raddoneurs or the "decades" of cyclists, I just know that this works for me (and it's not that radical).
Haven't heard back from McHale or Zimmer, but I'm looking forward to it.