Fact is: never autocast burrow on any other unit... it doesn't make sense. I mean I could see it make sense if it did things smarter (such as burrow roach if it fell below 50% health, and unburrow when it reaches 100), but people would complain to no end about that if it existed (takes out one of the only micro things zerg has at all... lol).
How did you do this? Being unable to unburrow units when I have a group of both burrowned and burrowed units is making me mad. Should be default like tanks, where you can seige the unseiged ones and unseige the seiged ones while they are both in the same control group.
Well to do it, you press tab... that alternates between the unit types (including burrowed and unburrowed units). I think shift+tab goes back? I can't remember if that even exists, let alone the hotkey.Now the reason burrow and unburrow are joined together is just a technical thing that can be easily changed (it's an option in the editor). The skills belong to the same ability group, and share command card locations. The actual decision reason as to why they did it? probably ease of use. the MAJORITY of the time when you want to burrow or un-burrow, you're either dealing with your whole army, or just a single unit, and pressing just 1 hotkey makes it a bit easier to manage I guess. It would be a nice option though, and in fact might be better forcing them to be separate even.