I'm a bit more worried about how effective the feedback from the infinite flights will be since we are moving closer and closer to the release date. I think that they should have released public flights earlier to collect a wide variety of feedback early on which makes it less likely that they invest a lot of time and effort into a feature which players may end up disliking.
Obviously they can't just push beta builds all the time, but I do feel that earlier public flighting would have allowed the community as a whole to provide a larger volume of in depth feedback based on the wide audience which they can reach with public flights. Additionally they would be able to address the feedback without having an incredibly small timeframe which seems to be the case now.
I do agree that earlier test builds would give them more time to incorporate feedback to make the game better. At the same time 343 has been making a pretty big deal that the Slipspace Engine will allow them to iterate and make changes to the game faster than they have ever been able to do before, so theoretically they don’t need as long a turn around time as a previous game may have needed. That remains to be seen though.
In terms of the player population for test flights, I’m sure it won’t be an issue to find games. People have been waiting for a while to play Infinite, so even if the initial flights are relatively small, I’m sure players will be playing a ton. MCC flights for new seasons tend to dry up after the first day or two, but that makes sense since the game isn’t really that much different from the live build of MCC and it’s more to test new maps to make sure they aren’t broken or a new feature or something smaller in scale. Plus later flights will only include even more players so games shouldn’t be hard to find at all.