Well, the more I continue to play HOTS, the more I continue to be impressed with it.
I have one main friend I play it with. Initially we were losing a lot, partly because of bad teams I think, but partly because we hadn't formulated a good strategy. I'd say we went on a spree of about 10 games, losing most of them, before something clicked.
Then we found something so unbelievably broken, that in every game since, we have almost never lost.
The Siege Tank (Sergeant Hammer) isn't really that popular right now. She's a "specialist", meaning her job is to deal damage to towers, usually from outside their range like all specialists. However, since apparently pushing is kind of nerfed right now, she's rarely picked. Her "siege mode", just like in Starcraft two does MASSIVE damage, and also hits in an aoe, making it ideal for prolonged teamfights, especially if she can stay at max range. This massive aoe DPS is balanced by the fact that she's completely immobile in siege mode, easily CCed, and especially the fact that there's only one of her.
Another specialist is Abathar, he's a character from SC2. Apparently he used to be brokenly overpowered, but he was nerfed at one point, and since then everyone has considered him trash and nobody ever picks him (I've never seen him in a game aside from when I play him).
However, when you put Sergeant Hammer and Abathar together, the results are impressive. In the early game, both Abathar and Hammer have mines, a lot of them actually, and in the lane you can simply mine the hell out of a bush (10+ mines easily). Hammer goes into Siege mode and starts chunking the creeps and heroes in the lane, and when the enemy heroes go into the bush to stop her BOOM, a million mines and you're absolutely dead. Easy first blood every time. Abathar has a talent which increases an allies attack speed as well, so Siege Mode + extra attack speed at level 4? Hello overpowered, the lane gets incredibly pushed, and early teamfights tend to swing in your favor, especially around objectives, because the extra attack speed, as well as a shield Abathar can provide makes the Siege Tank do massive damage. But the combo really gets disgusting at level 10. Abathar can make a copy of the Siege Tank, and then go into Siege mode himself.
2 Tanks in Siege Mode essentially means you'll never lose a teamfight again. All the enemy can possibly do is run. They simply can't stay within the huge radius of the tank shots, whole teams will get demolished. Hell, you don't even need team fights, you can just wait until the enemy team is distracted and "backdoor" a lane. Remember, you outrange towers in Siege mode. Essentially, as soon as the enemy team is distracted for A SECOND, two Siege Tanks in siege mode absolutely obliterating your base, and unless you send THE WHOLE TEAM back to stop them, you just can't. The damage is too strong, plus double widow mines and everything else. I'll usually go up closer so they focus me first, and even if I die it doesn't matter because the clone's healthbar is separate from my own, they just wasted a ton of disables and damage on a timed clone and let my friend run rampant.
It's such a hilarious wombo combo. Nobody expects it and in unranked, it can't really be countered without specific picks which they probably won't have. Even with specific picks, it requires a lot of teamwork to react to, and it's super easy for us to pull off.
Strategies like this are only possible because of the unique and interesting designs and mechanics of the heroes themselves, and that's what makes the game so good in my opinion.