Many people have pointed out that there is no reason to go tank/marine or mech in TvZ any more. Biomine seems to largely combine the mobility of MMM with the cost effectivenes of tank/marine. Before HotS there were 4 broad styles of TvZ available. MMM, tank/marine and mech. Being sequentially less mobile but more cost efficient and also less aggressive and more defensive style. All these three style have all but vanished from the face of the earth now because biomine is simply far more optimal than any of them.
At one point in the beta when mines were not that popular because people had the silly idea of using them outside of their army rather than just an army unit. A particular balance change saw te light of day:
Hots Beta balance Patch #19
Unburrowed Widow Mine attack priority decreased to 19, down from 20.
Burrowed Widow Mine attack priority remains unchanged.
Back then, I didn't realize how awful this idea is and what the implications of it are, the implications are simple, unlike with tank/marine. You aren't being punished for being caught out of position with mines because units do not attack them above ground. Unless you're Captain Zerus with all Jaedong's, Life's and DRG's powers combined. You can't realistically ask Zergs to focus down the mine with melee zerglings, it's just not doable. It actually doesn't matter all that much if the mines are already burrowed when Z runs in or are starting to burrow as Z runs in unlike with siege tanks.
Why? Because Siege tanks are best used when they can benefit from their gargantuan range. If Z can approach the T army without having first taken a volley of tank shots before theyt even get close, the engagement will go significantly worse for Terran. Furthermore, tanks have a minimum range so if Z can press close up to the tanks they aren't doing anything at all.
Added to that, mines have a very long cooldown. So if you start firing your first shot later you're not actually doing less damage during the entire fight, you just start doing damage later. Sure, it's sligtly less optimal to only have your mines burrowing as Z runs in, but it doesn't make the world of difference it does with tanks. By adding an extra unit in HotS, TvZ has been bereft of more options, rather than giving more. Because this one unit combines all the strengths of all the other styles into one. The cost effectiveness of tanks without being punished for being caught not set up and the mobility of bio.
In my ideal HotS TvZ, there would be four styles viable on a gradation of mobility vs cost effectiveness:
- MMM
- Biomine
- Biotank
- Mech
One, or at least I, would hope that at one point a patch comes which makes it that mines being caught unburrowed are actually punished for it significantly. On a side note, it's also why I think that drilling claws is an awful upgrade. What's the use of a setup unit if it sets up instantly? Wouldn't mind at all if mines did more damage but as a tradeof actually took considerable time to set up and had normal attack priority above ground.