I think you guys are making this waaaay too complex. I am interested in my partner's gear to the extent that I know he has his share of the group equipment (We are using your tent, right?), but I certainly don't need to see where he has packed his spare socks and toilet paper. If there is an emergency and my partner is incapacitated, I will be into his pack soon enough, as I would expect him to be into mine, if the situation were to be reversed.

For longer trips, a gear list is often a good idea - I was just looking at one I made many years ago for a two week excursion to Mexico to climb the high volcanoes, but for less involved hikes, a gear list is overkill. Generally, what you carry will vary significantly from one trip to another, although there is a core of gear, the so-called "ten essentials," which will go on nearly every trip. The gear carried on a sea kayaking excursion is not at all what is packed on a technical climbing trip, and certainly is different from a casual day hike.

Of real importance is having good agreement on objectives, the acceptable level of risk, emergency procedures, and the like. This is one reason that good hiking companions are somewhat hard to find, and are cherished when they do turn up. If she happens to be a hottie, so much the better.