The metagame has been shifting slowly in all three match ups (sorry, this is Terrancraft. Terran only).
The balance now is decent overall. The maps collectively do not favor a certain type of strategy (e.g., Blink all in), and to a certain extent I think some maps are Terran favored.
Terran vs. Zerg
With the recent Widow Mine buff, Zerg is less dominant in the match up. Previously, I dare to say Zerg is favored. The match up is much more even now, as Zerg really have to match Terran’s micro in engagement. Interestingly, Flash persisted with his Hellbat instead of using the main stream Widow Mine. Personally, I think Widow Mine is a better aoe choice for bio than Hellbat or Tank against Zergling, Baneling and Mutalisk. One of the advantages of using Hellbat is the benefit of upgrade. Mech attack upgrade does not affect Widow Mine, and hence, Terran get Mech armor for Widow Mine. The armor upgrade is less useful for Thor than the attack upgrade. Thus, the Hellbat and Thor go better together than Widow Mine and Thor.
Zerg has been changing their opening to pool first to counter Reaper expand. They make two to six Zerglings and go around not being spotted by the Reaper. The Zerglings force a cancel on the Command Centre on the low ground while the Reaper is on the other side. Watch these games for more information.
I played against this a few times, and the Command Centre cancel is very damaging. A Reaper expand build relies heavily on the Command Centre for the supply, so a cancel chokes up the build. This is a good metagame change because Terran basically assume Zerg go for a Hatchery first. This is evident when Terran no longer do a Command Centre first on the high ground. Logically, a Reaper opening is very ineffective if you keep it at your natural to defend against this metagame shift. So I think this is a smart metagame touch.
My answer is to go back to Scv scout. For a long time, I don’t scout on a two player map in TvZ. I only do a Scv scout for spawning point for my Reaper to go to the right place.
Another trend is the one thing that everyone is talking about. Swarm Host.
Swarm Host is usually used against Mech. But recently, Snute has popularised the Zergling, Baneling and Mutalisk into Swarm Host against bio. Swarm Host has actually been previously used against bio too, and this can be traced back to PiG. He used Roaches, then add in Swarm Host. I must say a Swarm Host transition from Mutalisk is very rare. If I see an Infestation Pit, I would have thought that it’s Infestors. It is still new, and many pros are saying that this is likely to become a mainstream style. Well, I’m no fan of Swarm Host.
Terran vs. Protoss
Probably by now you would have heard about the saying that Widow Mine eliminate Templar openings. I don’t agree, because it definitely exists and is still working. However, the charge Zealot and Archon timing attack is weaker now. It is kind of interesting that the very assumption that Templar opening is gone is the very reason why it is strong. Look at how INnoVation blindly added a second Starport against Stats in the recent GSL game. I expect to see Templar openings back in the metagame soon.
Command Centre first has become more common, and is often selected over Reaper expand. This is a sign that Terran are getting more comfortable about the builds that Protoss are doing.
Terran vs. Terran
This match up has been stagnant since the Banshee and Hellbat patch. Gas first has become the go to build now because it is superior in many ways. There are several aggressive variations, for example, Banshee and Hellion Marine drop. It can also open up for defensive macro. It is hard to be conclusive on what is coming. Further, the exchange of resources against gas first opening with a relatively more economical opening usually ends up even.
Recently, there is a popular strong TvT build that involves Raven’s Auto Turrets and Tank drop. It is a must know even though you don’t use it.
Flash has also brought up some interesting mech build in IEM. The gas first into a Reaper build has some nice defensive timing lined up well. The Viking is in time to meet a Banshee etc. The early Hellbat and Medivac combination shuts down the early Marine heavy push too.