At the current state with those big discrepancies in roster size of opponents I don't think this is a good idea. It would only make it more difficult for the smaller accounts while the bigger ones profit even more, because they still have enough squads to fill the slots, making it even more impossible for the smaller opponent to clear.
Eventhough I have more squads now than like half a year ago, I still don't have enough squads to full clear and set a full defence if I make only 1 mistake or can not use my solo characters , that only work on certain squads, let alone full clear high relic squads. I still have to set squads on defence, that are not (full) relic to be able to get by.
If you look at it from the other side, if the required squad number stays the same while your roster grows with Omis etc, it would give the chance to have more variety actually. For example you now have 4 instead of 2 squads to choose from, mixing it up on defence. If your opponent looks at your history, they never now what they will get or if you look up their history, you can taylor your defence more fitting to their roster or defence.
