^ATX22, "Well, sort of."
There is no good way to stop people from creating alt accounts (that doesn't punish the legit reasons), so they should work towards discouraging it. Make it so that creating a smurf isn't worth the trouble. That can be done in a way that actually helps legitimate newbies too.
FIRST: Fix the bug that lets players skip the tutorial.
SECOND: Make the tutorials deal with actual gameplay and longer, full match scenarios - so that a player must complete a series of objectives and prove that they've learned to play a complete match before they can get online in that game mode. So, if they want to play Siege, they have to complete a full-fledged Siege tutorial match and win it... before they can ever get into a real Siege match.
THIRD: Full MECH tutorials for each and every mech. Once a player buys a mech for the first time, they should have to go through (and successfully complete) a tutorial that takes them through objectives that make them learn how to properly and effectively use that mechs weaponry and special ability... before they can actually use the mech in an online match.
As for team balance:
The biggest problem with team balance (in my opinion) is matches almost always start with 4-6 players. Every match I've played that starts with a full lobby has really good team balance. Just as with the smurfing problem, you have to use incentives... and a simple penalty.
FIRST: Take away the "Daily Win Bonus" unless the player was in the match from the moment it started.
SECOND: Add a multiplier bonus that increases for every consecutive, full-length match that a player completes on the same server. The more matches you play in a row, the bigger your bonus gets (sure, it has to be capped somewhere).
THIRD: (As player population increases) make it so that more players are needed for a match to start. Or, have players vote to reduce the number of total players allowed before the match starts. The way the game adds players to matches in progress is totally logical, but we just don't have a high enough general population for matchmaker to find enough suitable joiners to allow matches to start with 4 - 6 players and still expect any kind of balance when a few more join at separate times later. The balancer simply cannot predict the future and, once a match is in progress, we can't expect players to be willing to sit in an indefinite holding pattern for a match while the balancer waits for enough players to do the same before it makes it's team decision.
FOURTH: Gotta have a mild rage quit penalty. It's contentious, but I think that if a player quits a match before it's finished, they should have to wait 4 minutes before they can join any other matches. I know that people will say, "things come up and I have to leave - why you punish me?" Well, anything that 'comes up' that is important enough to take you away from a match before it's over is important enough that it should take you enough time that 4 minutes isn't a big deal. And this would not apply to disconnects or crashes. A person would have to select "quit", or type it into the console, or force close the program before the 4 minute rule is in effect.