Been playing for a week or two and generally it is a lot of fun, but as a new game there are some issues with balancing I find:
1. Defense almost routinely is far harder to do in a pickup quick play match than Attack. Checkpoints that effectively save the capture progress on some maps combined with the half-mile hike between it and the defensive spawn already make it challenging, but without sheer luck in getting a team of competent people who won't quit halfway through if the first point falls, a sufficient defense can never be formed because inevitably there's going to be a sniper picking off individuals (usually a Hanzo who then fires off his ult). And part of this has to do with a person dropping out BUT NOT BEING REPLACED IMMEDIATELY by an AI, for the sake of just having a consistent body count, because one less person to deal with in any form makes it even easier for the side whose only objective is to bum-rush straight ahead. Granted, I'm not even level 20 yet so I'm hoping the higher levels will get me more capable defense teammates in pickup rounds.
Note: This is only about KOTH type control points. Payload portions of maps are A-OK in my book right now.
2. Junkrat's Ult. is an exploding tire...unless it is killed by enemy fire first, in which case shooting guns at something that explodes doesn't cause an AoE explosion. Whereas killing Junkrat does by default. Given the tire's relative low health, it feels like it should explode no matter what to balance that.
3. Hero choice restriction. Seriously, if the whole point of having multiple heroes cover different roles is to change on the fly to adapt to enemy 'strategy' when there is one, then outside of those special brawls there shouldn't be more than two of one hero character ever in play.
4. Some form of tutorial at the beginning that covers the more technical heroes - primarily Zarya. It really is not clear in any form of in-game documentation beyond the mention of her passive that her gimmick is literally using herself and allies as bullet sponges with the shields, charging her laser canon and thus buffing her damage past that which I'd expect would come from Zarya just using the gun a a bludgeoning device instead of a gun.
5. Reinhardt's charge needs a cancel option. D.Va has one, Pharah's jets are manual control at all times, even Winston's jump can be canceled mid-flight. But having to remember where the map simply makes him fly off a cliff unavoidably renders the guy really frustrating to use around control points in Greece and Japan since often the charge is started BEFORE it is realized he's going to fly off into the abyss.
It's also REALLY AWKWARD that only Widow has iron sights for the sniper, I keep pressing the right mouse button on Soldier out of instinct and end up firing the rockets by mistake.