Infestors are exceptionally strong and cost efficient vs many Terran and Protoss mid game armies. With a few infestors Zerg are able to effectively defend against almost all Terran and Protoss timing pushes in the mid game and safely and very quickly tech to Hive and end game brood lord or ultralisk compositions. Zerg reaches these late game compositions significantly faster than the counter compositions from Protoss and Terran, in large part due to getting out high number of cost effective infestors in the mid game and continual corner cutting in other defensive aspects.
The proposed solution
Make the pathogen glands upgrade require hive tech.
Pushing the pathogen glands upgrade forces the zerg to make one of three choices.
1) Continue making infestors on lair tech but without the ability to immediately fungal making the zerg vulnerable to mid game pre-fungal timings. In order to be properly prepared against these timings zerg would need to invest in more defensive units or structures delaying upgrades, or continued progress toward late game compositions and higher tech units.
2) Quick tech to hive and pathogen glands. This option effectively delays infestors by at least 100 seconds and requires zerg to invest 200 minerals and 150 gas in the Hive tech before producing infestors. The additional gas and mineral sink means that zerg may have to cut some other upgrades or produce less infestors and more importantly the window of zerg vulnerability is very large with this choice. By rushing hive tech zerg will need to produce significantly more defensive units or buildings in order to properly prepare for mid-game timings that would hit before infestor production commences. Additionally this gives protoss or terran opponents the option to try to out-greedy the zerg at this point knowing that the zerg without infestors poses a significantly less potent threat.
3) The zerg completely ignores infestors for the mid game instead opting for a hydralisk or mutalisk based composition. Transitioning to the late game infestor + ultra/brood composition will then be delayed as infestor production did not start in the mid game.
I truly feel like this change could do wonders for the current state of things in SC2. This change in combination with other small buffs to units like Ravens or Carriers could go a long way toward balancing the matchups.
Thanks for reading and please leave any feedback =)