adding multiple factions as an option (IMO) is not good-
for the reasons above-
in addition, as an organizer you want to turn over the time the players are using quickly and efficiently
imagine going from table to table with a Rasputina squad (Usually 5-7 models) to a Leveticus or Colodi squad (7-13) between each table!
keep in mind, not every venue has the space of GenCon or some other Large scale con, they are played in local stores with other things going on
the rules as written, lay out that you hire your squads after the main "Goals" of the game are introduced...
the debate could go on& on... mostly becoming an 'Us' vs 'Them' issue- I prefer to stick to what IS
From what I've seen and been able to play test, the OP Tournament format being set up is VERY fair and equitable for either type of player and keep to the origional format as outlined in the rule books