The situation report for StarCraft II patch 1.4 is out, explaining the balance changes of the latest patch.
Infestors were all around too general. Neural Parasite takes care of the more expensive medium size units as well as massive units, Fungal Growth is good vs. small to lower cost medium units, and Infested Terrans were just good for cost vs. anything that doesn’t move out of position. We like the positional-based gameplay Infested Terrans cause, so we decided to look at the other spells instead.
Fungal Growth is a solid spell that is a core part of the zerg meta-game, so we went with as minimal of a change as possible. We didn’t want to change the current game too much since according to our stats all zerg matchups are very close to even at the highest levels. When testing with the highest level players, we noticed this change is very minor yet still very slightly noticeable.
We decided on the Neural Parasite change in order to create more decision making in terms of the positioning of the Infestor as well as what units are needed at which locations in order to better protect the Infestor casting this spell. Previously, it felt too easy to cast and too difficult to counter without having siege range units.
You can read the entire situation report at its respective Battle.net post.
Battle.net - Situation Report: Patch 1.4