Round robins tend to work out pretty well, but as more and more teams are added, they get messier. I think it's nice for small number of teams such as proposed, so it would make a nice finale, but for the main part of the tournament it would be rough. This is doubly true since we're using smaller teams and combining them. Trying to get all teams to pair up with all other teams and compete against all combinations of other teams.
So if we get something like 8 teams, we'd need:
AB vs CD, CE, CF, CG, CH, DE, DF, DG, DH, EF, EG, EH, FG, FH, and GH
AC vs BD, BE, BF, BG, BH, DE, DF, DG, DH, EF, EG, EH, FG, FH, and GH
AD vs BC, BE, BF, BG, BH, CE, CF, CG, CH, EF, EG, EH, FG, FH, and GH
AE vs BC, BD, BF, BG, BH, CD, CF, CG, CH, DF, DG, DH, FG, FH, and GH
AF vs BC, BD, BE, BG, BH, CD, CE, CG, CH, DE, DG, CH, EG, EH, and GH
AG vs BC, BD, BE, BF, BH, CD, CE, CF, CH, DE, DF, DH, EF, EH, and FH
AH vs BC, BD, BE, BF, BG, CD, CE, CF, CG, DE, DF, DG, EF, EG, and FG
That's 105 matches just for all possible combinations of team A. Each team would need that many matches. There would be a lot of overlap of course, since we're getting 4 teams in on each match. My lazy-I-Just-Got-Up-This-Morning math that's probably wrong is looking at 210 matches? (8 teams, 105 matches, 4 teams to a match 8*105/4?)
With 8 teams we can only 2 matches at a time (2v2 and 2v2), we'll say each match only takes 15 minutes exactly, letting us get in 4 matches within an hour. Give it 2 hours a day for a grand total of 8 matches a day, and we're looking at needing 27 days. And that's just with 8 teams (the equivalent of four 'regular' teams). Add in more teams and it just gets longer and longer, that's the downside to round robins, which I tend to agree are the most fair by far, which is why I like them for finales.
That's with every team with every combination. We could just make it easier by splitting up the teams into divisions of 4, where they only need 3 matches, then structure that into a bracket style tournament. The top two teams from each tier moving on ahead, and just repeating that process until we have only four ships left and get our winner from that. The downside to a bracket system is that it's not very league like, as a lot of teams would be ejected very early on. The upside is of course a lot less matches, making it doable. Say with 8 teams, we'd have 3 sets for both teams (6 matches), the top two teams from each division move up a bracket to make another set of four and we get 3 more matches. If there's too few teams, we can make it double elimination or double round robin. If there's an odd number of teams in any division, we can set up a pre-lim bracket the week before the scheduled tournament and have all of those ships compete in a round robin. Only the top 4 move on to the actual tournament.
I think it would work really nice for a tournament structure, but wouldn't be great for a league.
On the other hand.. it might get less messy if we toss teams into 4v4 matches for a pure round robin system? I'm not a particular fan of 4v4's, as it's harder on a lot of peoples systems and the game isn't quite as balanced with that many ships in same area, but it would potentially make a pure round robin system doable. It would also eliminate the need for bracketing, allowing for everyone to keep playing every week (with a bye week or such) making it viable for league play.