HandcuffedHave y'all considered running these as first to three rather than first to five?
The biggest issue with the newbie mixes (in my fairly uninformed, new-to-mixes opinion) is how much time you spend wasting just trying to get a mix going. And after it ends, you often wait around for another mix or two to end or for new players to join... and then might not get picked depending on who else joined new to the mumble or just by luck from organizers amongst a pool of players.
Tonight, due to some issues getting a full team (players considered "too good" were kicked, needing to pause when someone lagging out, and an even match that ended up tied 3-3 after 30 minutes or whatever the time limit was), I was able to play a single mix in two hours of queueing. The mix was a lot of fun, the coaches were helpful, etc. but I spent most of my time sitting in mumble (and realizing that maybe I'm too old to be playing or interacting with this community,,,). I think turning the games over more - playing first to three - would help get more games going. Plus, matches where one team is blatantly better than the other would be over quicker and there'd potentially be more coaches available as the time commitment to coach a mix is lessoned.
The downside, of course, is that a first-to-three mix is not replicating an actual 6's match but I don't think the primary intention of these mixes is to win or anything. It also does take a lot of time to pick teams and get everyone ready in a server, but I would think you could gain some efficiencies with matches ending quicker and more people being able to play at a time.
The goal of Newbie Mixes is not to get as many mixes out as we can, but to make sure all of our mixes are as good as can be. We cannot control time delays from disconnecting or people aliasing, and even without delays, mixes take a long time simply due to the nature of them. Teaching people is not a short process. They could be sped up, but you run the risk of skipping over a lot of valuable information that the newbies would love to know.
Changing the rules to 3 rounds would not be a good idea in my eyes. From a coaching POV, it is hard to coach from just 3 rounds. 3 rounds is not enough time to really see how each player on a team plays. It is already hard to watch all 6 players with 5 rounds. On your point about rolls, I think 3 rounds would only make that worse. If it is an absolute roll, 3 rounds may be faster, but an extra 2 rounds does not take that long either. Also, having 5 rounds allows more chances for a team to break out of that roll, maybe getting a round or at least a chance to see how a proper defense can play out.
Lastly, I do apologize for the time you spent waiting in between mixes. It is hard for admins to see each and every player who has been waiting, and has become even harder due to our increase in newbies. Most admins try to draft by how many games people have played that night, which usually seems to work when trying to get people who have been waiting. We can certainly try asking if people have been waiting a long time to be drafted.