First off, the EdCamp/unconference was fantastic. It was well facilitated, and I had great discussions both during the formal sessions and on the side. It was also a nice way to connect with some people from other colleges around professional topics, then see them again later in the week and follow up.
The backpack: 'm not too big on swag; most of it goes to perks for faculty or tech support folks who do something special. But I'm keepin' the backpack. It's practical and nicely made.
Ski resort/outdoors location - I've enjoyed the ski resort/outdoors locations for the conferences. I think Keystone was a bit rough around the edges (see below), but the idea of getting away from it all to focus on a topic, and getting some fresh air to clear the head between sessions is great. I'll be sad when it ends up in Just Another Conference Center. And home if it ever lands in Vegas.
The app was really nice this year. The UX on the apps from previous years was rough, but this made it possible to go paperless, at least for those who had a smartphone. I agree with the earlier comments that a paper version on request would be helpful for those who are wi-fi only or don't have a smartphone.
Session tracks/levels - Several of my colleagues have mentioned this as well; some basic leveling would be nice. Even two levels - "Newb" and "Geek" or something like that would be helpful in picking sessions.
More concurrent sessions? - It would take a different kind of venue, maybe, but one possible way to make both tracks and the crowding issue easier would be more sessions at the same time. Also, we could probably thin out the keynotes a bit. I got the same info at the product keynote and the roadmap sessions.
Food allergies - This was a serious bummer. It took until Thursday morning before I could reliably find a meal. I was able to connect with the chefs, and they tried (shout-out to Stefan and Greg in catering), but this shouldn't be a difficult accommodation for a conference of several thousand people. Generally, some amount of creative menu planning, and some build-it-yourself options at every meal will cover it. I know that "At Canyons I could..." starts to sound like "In Angel I used to be able to..." a little, but they really did have it nailed. Not only was the food allergy area stocked with lots of ways to navigate around different food allergies, but they were quick on the draw for the one meal I couldn't eat. And the alternatives were *good* - like people in the regular food lines were jealous good - and that's kind of a nice change from the norm.
Room share was awkward - We sent a pretty good size team, but with the mix of arrival times and genders, we were only able to pair up two members of our team. There's only so much sharing that you can do in a professionally appropriate manner. Also, it was unclear who paid how much if one person in a share was there Mon-Fri, and another was there Tues-Thurs. I had funding to send one more person, but we couldn't find a room. Which leads me to...
Cost - This has been a very valuable conference over the years, so much so that we've sent big teams. However, it's getting pricey enough that I'm probably going to send a smaller team next year. I'm looking at total cost: registration is a lot for what amounts to two days, and lodging was super high, even accounting for the great location.
One last note that I heard and (at least in some low-light areas) experienced: The print on maps, schedules, etc was tiny and low contrast, making it hard to read, at least for those of us old enough to sign a travel requisition. Please consider readability over hip colors next year!