There are two ways to defend as Terran: have enough repair power to simply stop walls from dying, or have enough firepower to kill the Zerg before they get to you. The issue is that Tanklings are currently too good at both. It's plainly obvious why Tanklings are very strong against the repairing strategy, so I will expand on why they are currently also strong against the firepower one.
When compared to simply massing Slowlings, Tanklings have essentially the same HP/sec. However, Tanklings do experience slightly more idle time due to having a cap of two, so the real number is perhaps 10 or 20% less than Slowlings. However, they have a couple of very distinct advantages:
- They are not as susceptible to Shock Trooper blasts
- Grouping up Tanklings allows for big wave pushes of much more combined HP than slowlings
- Correctly split-microing Tanklings in wave pushes makes them incredibly difficult to deal with, due to the above
- Terran has very little time to respond to Tanklings before every expensive low ground building is destroyed
- With Armor 1, Tanklings become on par or better than Slowlings with respect to effective HP/sec
In general, they are too strong of an all-rounder unit, so naturally they are used to kill dangerous expanding Terrans rather than no-push-potential bunkering ones. In this way, Tanklings encourage Terrans to bunker by allowing Zerg to full-focus aggressive Terran much more effectively, while still being ineffective versus Construction Yard-buffed walls. Why would I play aggressive and expand when all that would do is cause Zerg to build a bunch of unkillable Tanklings and destroy all my low ground?
The overall problem seems to be that while, yes, Tanklings are now more effective against turtling Terrans and their walls, they have become
even more effective against aggressive expanding Terrans. Tanklings can kill an expanding Terran's temporary walls, but not a turtle Terran's Construction Yard walls.
Potential solutions I can initially think of include:
- Tanklings deal %HP damage to walls instead of massive early game flat damage
- Tanklings ignore Construction Yard damage reduction aura
- Tanklings have ramping damage like Creepers
All of these ideas would cause Tanklings to be specifically more effective against a Terran relying on powerful walls while having little Army to kill things, which is more in line with their intended use.
One final point I would like to make is that currently
there is still no reason for Zerg to go after bunkering Terrans. Without the accompanying Mega Tank buff, low-gas turtling Terrans are still entirely harmless.