Suggestions for addressing matches with significant score disparities.

I like the behemoths in Battlefield 1.

I don't think game loops like that are a great idea. It's good to think about it, and then the possible solution, but that solution feels a bit artificial and most players will end up feeling frustrated by that. It's an issue that's plagued BF forever, and it's crazy how little they've done to address it over the years. No worries though, we get a brand new mechanic of dragging downed soldiers behind cover! All is solved!

The problem exist for two main reasons in my opinion:

1. Bad map designs. Bad spawn points with poorly designed main base areas. Look at Stadium. No idea how a map like that gets play tested, then signed off. It's an abomination top to bottom regarding design. There's fun elements to it, but no awareness with balancing. 
2. SBMM is a must, and it should always be a thing. The community needs to get past weather it should be in the game, and focus on how it's implemented. Teams overall should have similarly skilled players. One team could have 2 diamond players, 2 gold, 2 silver, and 2 bronze. The other team with 3 diamond players, 1 gold, 1 silver, and 3 bronze. The idea being the total skill rating is close to equal between the two teams. There needs to be constraints to that as well. You can't balance one team with 4 diamond and 4 bronze, that's too big of a gap and both pools of players will find that very frustrating for very different reasons. 

If players leave the game midway, it will definitely upset the balance. As has been the case up until now, we need ideas to reduce the number of people who quit midway.

It probably doesn't work that well, because many people prioritize personal performance over the flag when they're losing. Fort Vaux in BF1 is a good example.

Well, to some extent the map design contributes to the issue. We have had some really terrible maps where it was very easy to lock a team into their spawn where it would become extremely difficult to get out of. So making sure the map design doesn’t allow this is a good first step. I don’t know how vehicle deployment works in BF6, but I remember how bad vehicle stealing from spawn was a thing in BF4. Not looking forward to that either 😅

But I do hope they deal with balancing in public lobbies because it would be a terrible experience otherwise. Leaving the balancing to the community is not really something I’m looking forward to either (badmins?)

They should just leave the balancing to the community, as it was in Battlefield 2 or Battlefield 3. Privately owned servers run by players for players.

It’s a bit concerning to me that this is actually a thing in this new installment. I hope this gets addressed because that’s what has always been a terrible experience in every Battlefield game.