There is a spell queuing functionality problem which causes if you use a group of spell casters to progress spell queuing for more than two kinds of spell, these casters will not be sent out one by one as it does in the case you only progress one kind of spell queuing. Detailed, when you only cast one kind of spell, for example, if you use 8 ghosts to cast 8 times steady target, 8 ghosts will be sent out respectively to operate eight times steady target, rather than 2 ghosts only, even if one steady target simply cost 50 energy which can be cast by one ghost for 4 times. This is the basis macro mechanics of spell queuing in sc2. However, if the case turns to be queuing with two spells, for example, if you use 8 vipers to cast 4 times blinding cloud along with 4 times parasitic bomb, there will not be 8 vipers sent out to complete the task separately. On the other side, only four vipers will move out to take all the burdens, which is 4 times blinding cloud and 4 times parasitic bomb, and then desert all 4 times parasitic bomb due to insufficient energy. Which is, that you‘ve issued an invalid command.
This is because system treats these two different kinds of spells queuing separately. They are not put in the same queuing set. This is so improper for a macro game like sc2 to operate. Death cost of specific individuals becomes higher than it should be. For a macro game, macro functionality is provided by the most general command. If players have a specific demand, they should do it themselves specifically. If I wanna use one viper to cast 2 spells, I should click a specific viper to queue a specific command just for it, rather than the current problem like this. 4 vipers take a huge death cost, the other 4 doing nothing. status quo is even worse, they just ignore the command.