I was just looking at my 2014 comments, so I thought I'd compare a bit:
2014: "First day [reg. day] was almost entirely wasted due to long and slow registration lines."
2016: Registration was fast and painless. No line at all. Probably partially due to no character-specific badges or T-shirts. However, there was no reception on registration day as there was in 2014.
2014: "Fix the merchandise booth - allow pre-orders/on-line orders of merch (limited to one item per person so you don't run out of goodies) so you can pick it up any time during the weekend; fix the stupid credit card machines... It was also a mad free-for-all as people cut into the front of the line."
2016: More working machines (but 3 still broken); but the merchandise line somehow got even worse; still a mad free-for-all with anti-social behavior; preorders not implemented, items still ran out... basically a disaster.
2014: "Fix the priority system for first-timers on each line; first-timers (at the very least) should be able to register for a time slot. The priority system was poorly organized and didn't really work well."
2016: Priority system not implemented at all as far as I could tell? I didn't get to do Trials roulette, sadly.
2014: "Fix the ticket system - web site melted down...."
2016: Ticket site worked OK, and tickets didn't sell out until later in the day.
2014: "Create a bigger area for server meetups with movable signs for each individual server....more organized approach...Pre-registering for per-server meetups..."
2016: Same comments apply.
2014: "Optimize communication - some things went out over e-mail, others were in the printed schedule, other things were on the web site, other things were announced over the PA, and still other things weren't announced at all!"
2016: Schedule didn't go up until late, but it did go up. Overall: OK but could be better.
2014: "I felt vaguely dirty about the VIP pay-to-win system"
2016: No VIP tickets, no great loss really; would have liked to see more official signing/dev interaction opportunities.
2014: "The raffle items weren't as awesome as they could have been"
2016: Raffle replaced by Jumbo Cactpot, which wasn't bad. Still no awesome mega-prizes though, and I missed the excitement of cheering people on as they won prizes in real time.
2014:"Can we get an Eorzea café at the fan festival like the one in Japan? That would be totally awesome!!"
2016: Food room adjacent to the show floor, but still no Eorzea Café sadly!!
2014: "One unfortunate guy (my paladin in in-game event) got his Moogle stolen while he was watching a presentation!!"
2016: Badge had FanFest code of conduct printed on it as well as enforcement. I didn't hear about any thefts, but line-cutting was rampant in the merch line.
2014: "It's sad but almost laughable that I got gilseller spam waiting for the Odin battle!!"
2016: No RMT spam in game instances! Right-click report may have actually helped?!?!?! At last?!?!!
2014: "Can we get access to the stream archives?? Please?"
2016: Worse - now $30 rather than $20, and no discount or credit for in-person attendees.
2014: "Huge props to everyone who helped to put this on - it was immensely fun and I just wish my whole FC had been there to enjoy it!! Thanks especially to the magnificent Yoshi-p, Mr. G(ondai?), Soken, and Koji Fox, as well as all of the members of the Primals!! Thanks also to the 3+ star crafting cosplayers and to the friendly and helpful fans who made the lines more tolerable and who were also terrific in the in-game events!! "
2016: Gondai was MIA sadly (though we got Nakagawa "Mr. Ozma" instead) - but it was still a great experience overall and... some people from my FC actually made it!!! And more people from my server!