I'm a member of the MACNA 2018 staff and have worked 5 shows in a row so far (every show since 2014 in Denver). I am not an official spokesperson for MACNA or MASNA (the parent organization), just a hobbyist in Denver with no affiliations one way or the other, and wanted to address a few things based on my own personal opinions and stuff I saw behind the scenes:
Noticed it was not to crowed. But the place looked gigantic causing it to look empty.
Yes, the venue was huge, and the attendance was actually really good. We purposely set the show floor up with many of the aisles being 15 feet instead of the typical 10 feet, so that it would be easier for attendees to get around. Pre-sale tickets orders set a new record (previously held by the Denver show). I have not yet seen the final attendance tally which would include the on-site day and weekend pass sales but they were good - in particular most exhibitors were saying that Friday (normally the slowest day of the show) was the busiest Friday they can remember. Something like 4000 swag bags got stuffed before the show and we ran out during Sunday morning.
I don't know the details, but I believe after the New Orleans MACNA they took organizing/running the show out of the hands of the venue's local club. That may have been a mistake, because without a financial windfall what motivation does the area's local reefing
community have to make it a successful MACNA? Since it obviously needs a strong local show of support every year.
This MACNA was the first show where MASNA (the parent organization) ran the show instead of a local club running the show - the idea was to try to maintain and improve the show quality by providing more consistency and continuity from year to year, instead of each club having to reinvent the wheel every year. (Plus, the show is just getting too big to expect any local club to be able to manage running it on their own, or to find a venue big enough to hold everything.) But we had
awesome support from the LVMAS folks, who provided dozens of volunteers and put in a whole lot of hours of work to help make it the success that it turned out to be, and we could not have done it without them. (PS, if you are not at MASNA member, you should be:
https://masna.org/) (PPS, Thanks LVMAS folks! You rock!
https://www.reef2reef.com/forums/las-vegas-marine-aquarium-society.672/)
Sounds like nothing more than a huge frag swap than a public trade show. There is so much innovation in development and nothing offered as far as demos, delivery dates and the like.
I guess you have never been to a MACNA.

It's definitely not just a big frag swap. Over 150 exhibitors, maybe 10% are coral sellers (including Jason Fox, Unique, World Wide Corals, Zoanthids.com, etc.), and the rest are all the industry names you are probably used to seeing, tons of cool stuff on the exhibit floor (
https://macnaconference.org/2018/floor/). 31 speakers gave talks, including basically everybody you have ever heard of in the hobby (or people you
should have heard of, if you haven't yet): Julian Sprung, Sanjay Joshi, Marc Levenson, Martin Moe, Bruce Carlson, Dana Riddle, Jean Jaubert, Richard Ross, Mark Callahan, Walt Smith, Charles Delbeek, Bob Fenner - the list goes on and on (
https://macnaconference.org/2018/schedule/). Keynote speech by Charlie Veron, coral identification god.
If you haven't been to a MACNA, go. If you have been to a MACNA, go again. Hope to see everybody in Orlando next year:
https://macnaconference.org/2019/
Larry