Not a balance discussion, this is about fun although balance is certainly a part of it. 

What’s The Situation:

• Common knowledge at this point that zerg is not very fun to play right now
• Some tournaments offering bounties for zerg players just to participate
• Zergs are saying the game feels restrictive as they are forced into reactive styles
• Long exhausting macro games are the norm
• Inability for zerg to punish greedy T or P macro styles, while also having to watch out for T and P aggressive styles. 
• ZvP and lategame ZvT are particularly bad right now.

How Did We Get Here:

I think balancing around the top 4 players and attempts to make the game 'less frustrating' led to a few things:

Minor nerfs for P and T aggressive options, heavier nerfs for Z aggressive options:

• Chargelot all in vs Ling drop all in:
  • The Overlord’s Mutate Ventral Sacs upgrade now requires a Lair instead of an Evolution Chamber.
  • The Charge upgrade no longer provides Zealots with +8 damage on impact. Instead, it increases Zealot movement speed from 3.15 to 4.72, up from 4.13.
    • Charge extra damage removed vs OL transport is now locked behind Lair. Impossible to get Lair and OL speed and ling speed in time now for the build to work. 
    • Dmg nerf to charge changes nothing about the build execution or timing, but reduces its power. Lair requirement to OL drop forces 1 less queen and MUCH less macro power if you still want to hit the same timing. 

Prism vs nydus:

Prism:

• Cost increased from 200 to 250 minerals.
• Pick up range decreased from 6 to 5.

Nydus:

• Nydus Worm cost increased from 50/50 to 75/75.
• Summon Nydus Worm ability cooldown increased from 0 to 14.
• Nydus Network and Nydus Worm initial unload delay increased from 0.18 to 0.36.
• Nydus Network and Nydus Worm load period increased from 0.09 to 0.18.
• Nydus Network and Nydus Worm unload period increased from 0.18 to 0.36.
  • Goal was to slightly reduce prism power but not remove prism builds vs the goal was to remove nydus builds while keeping nydus lategame utility.
  • Pickup range reduction and slight cost increase vs a series of experimental redesigns until we found a version that was only usable lategame 
    • Queen AA range also reduced a year later to compensate for prism range reduction
• Ravager cocoon nerf:
  • Build time increased from 8.57 to 12.14 seconds and removed the random delay of up to 0.36 seconds.
  • You can’t make ravagers in the fight anymore to save roaches
  • This is what allowed early game roach builds to be so successful
  • Another early game aggressive option removed
• Lurker timing nerf:
  • Lurker range decreased from 9 to 8.
  • New Upgrade found on the Lurker Den: Seismic Spines
    • Increases the Lurker's range from 8 to 10.
  • This change massively reduced the midgame power of the lurker and lurker timings in ZvP have suffered as a result. This is one of the few ways that zerg has to end a game vs protoss before lategame without having to resort to some sort of early game all-in.
• Hydra timing nerf:
  • The "Muscular Augments" upgrade has been split into two separate upgrades:
    • Muscular Augments
    • Grooved Spines
  • This change removed the 7 minute hydra timing from the meta, another of zerg’s favorite ways to end the game vs Protoss before lategame

Shield Battery:

• Without the ability to snipe the mothership core and disable defenses it is actually much harder to break a protoss now. 
• Shield battery defense is strategically simpler, easier to micro, and stronger than the old pylon overcharge defense used to be.

Queen and Creep Nerfs:

Queen:

• Transfusion no longer restores 125 health instantly. Now, it restores 75 health instantly plus an additional 50 health over the next 7.14 seconds.
• Anti-air weapon range decreased from 8 to 7.
• Can no longer transfuse off creep
• Cost increased from 150/0 to 175/0
• Mountain of nerfs starting in nov 2018
• Forced investment in a gajillion queens. 
  • Any time you require an investment in defense for a macro style to be viable, that cost will slow their pace toward lategame and will create a divide between aggressive and macro styles and make the race less flexible between them. 
  • Forcing zergs to make 7-10+ queens just to play a macro game means any time they want to be aggressive and then transition into macro they somehow need to magically squeeze out all those missing queens. 
  • This encourages all ins or defensive macro and discourages timing attacks or any sort of intricate multi-stage builds. 
  • These kinds of builds are the spice that breaks up the monotony of macro games and if we want TurtleCraft II to be a meme of the past we should think about encouraging these builds again.
• Queen cost nerf also adds to this ‘macro style investment cost’ and further discourages aggression into macro builds. Also a bit annoying for some builds but most are offset by the hatch cost change.
• No transfusing off creep completely removes queen walk builds from the game. Whether you like seeing them or not, it’s yet another zerg aggressive option removed. 

Creep:

• Time in between creep growth increased from 0.3 to 0.45.
• Active Creep Tumors may no longer be canceled.
• "Armored" attribute removed.
• "Light" attribute added.
• Cooldown increased from 10.71 to 13.57 seconds.
• Sight range reduced from 11 to 10.

Infested Terran Removal:

• Flexibility of the infestor is gone. 
• On-demand anti-air is gone, now forced into corruptor viper
• Previously, vs an air switch if you had a strong army plus infestors you could attack and with the infested terrans you could force a bad fight to win the game. 
• Now this is no longer possible, microbial shroud doesn’t come close to compensating. It’s just a ‘storm here’ target.

Lategame Range Wars vs Terran:

Thor:

• High Impact Payload weapon range increased from 10 to 11.
• High Impact Payload damage decreased from 40 (+15 vs Massive) to 25 (+10 vs Massive).
• High Impact Payload weapon cooldown decreased from 1.7 to 0.9.

Broodlord:

• Range reduced from 11 to 10.
• Broodling leash range decreased from 12 to 9.

Viper:

• Reduced "Blinding Cloud" ability duration from 10 seconds to 6 seconds.
• After casting Abduct the Viper can not move or use abilities for 0.57 seconds.
• Broodlord and Thor interaction flipped on its head and now broodlords are countered by the unit they are meant to counter
• Previously, the broodlord is what allowed zergs to break through stalemates and end games. Now, even if the zerg is ahead they have to play a very slow and methodical exhaust style because it's not possible to break the Terran defenses efficiently enough. 
• Viper power reduced vs stronger thors and ghosts, further adding to the stalemate issue.

So I Ask You: What Can We Do About It?