The current autobalance seems rather close to the old. It might be a placebo effect but teams in general are slightly more balanced and 5-0 win streaks are a bit rarer tho.
The autobalance system is clearly fucked up. The way it balances (at least I've noticed) is that when one side is winning, it will throw everyone that's good onto the other side and that side will completely dominate the round.
As an example, one side was easily winning the map then the round ended and it switched teams around. The team that was winning had 3 people with 7 for kills, and the rest of the team had 3, 2 and 1 kills. The other side had the first three people with 15 kills, and the rest of the team all had almost double the kills of the previous winning team. If you looked at the scoreboard it was obvious the autobalance just put all the people getting kills on the team it wanted to "make stronger". Of course the team that had been losing won the round easily.
Autobalance doesn't mean when one side is losing you switch people over so they can't lose. It means making both sides about equally balanced. I think the equation is basically just trying to keep the wins and losses of both sides about even, and not actually trying to make both sides "as equal as possible".
Also to the one posting about siege balance, it's always been that way where it will switch you from attackers to defenders (usually at least once per map) so it's hard to keep a multiplier going because the maps are very unbalanced. Most siege maps have a clear advantage for the attackers or defenders.