Legacy of the Void Beta Patch 2.5.2 - Page 4

Corruptor
Reverted ability to Corruption but now can be auto-cast.

On May 16 2015 05:46 Grumbels wrote:
In Warcraft 3 you had specific hotkeys for each of your heroes, many abilities could be auto-casted and with limited unit selection you were forced to create separate control groups already. And fights would last longer so you had more time to cast the spells. In contrast, some of the concerns with active abilities in Starcraft 2 are related to the interface and specifically the tabbing system. You have the power to select your entire army with one convenient hotkey, but to actually use those abilities you have to go through a cumbersome process of tabbing just the right number of times.

There are other RTS games where all hotkeys are global, that is to say that if you hit "G" you might always activate guardian shield for all sentries in your control group. Of course this can't be simply adapted to Starcraft 2 but it's an example of an approach that acknowledges the fact that abilities can contribute positively to the game and that tries to make them accessible to players.
There are also abilities that could be given auto-cast, like the void ray's prismatic alignment. You can still activate manually for correct usage, but you wouldn't have to stress out during fights because you had to cycle through all your abilities quickly.

These are examples of ideas that Blizzard could employ to allow users to better navigate through a game infested with abilities. Because adding abilities comes at a cost of requiring ability upkeep in battles, which starts to drown out real micro.

Reverted ability to Corruption but now can be auto-cast.