Overall, I think the new autobalance system was an appropriate, if not necessary change to the server. I think both blue and red share a little blame to how it ended up here. It's not perfect, but I think this system is a big improvement over the prior situation.
The main problem was that over time, two distinct factions formed for the red and blue teams. I don't know the stats, but very clearly the blue team would trounce the red team handily a majority of the time. This made playing on red unenjoyable, especially if you were trying to do well.
The blue team routinely stacked the better skilled players, and tended be more focused on the game at hand. The red team tended to be more chatty over the mic towards non-game related topics (i.e. water cooler talk). While great for catching up with friends, this unfortunately would distract from the game itself a bit. In other words, red were team stackers too, just in a different way.
Forcing an autobalance of players has resulted in better games overall. There are still steamrolls, but at least they aren't entirely predictable. The team shuffle seems random enough where it feels like a different enough game every time you play. And you get to play with folks that maybe you wouldn't have normally played with in the stacking era. One downside though is that you might not get to play on the same team with your friend or group of friends. Plasma said you can use sm_addbuddy to pair up with a buddy, but I haven't tried it myself.
Problems that have already been mentioned:
- autoassign based upon skill/ranking/points. This could be a good thing, but might also be bad. The teams might become too predictable over time if just using a numerical system to assign teams.
- reconnecting to swap teams. This can and does happen currently. It could grow into a bigger problem, but for now it seems minimal.
- "no voting in the middle of the map!" (in my best Vector voice). Not related to autoassign, but the map vote popup has been one of the biggest nuisances for a long while. Sure, we've gotten used to it, but problems are: You can't swap weapons while it's up, and people might just select the first map listed just to make the vote menu go away. In a perfect world, the map vote would come up after the 2nd round has ended (after one attack/defend per side), the map vote happens during the downtime, and then off to the new map.