As someone who has played more Terran than Toss in his life, there will never be a better form of vision/scouting than scan. Simple as that. It is more balanced now that there is an opportunity cost, essentially costing you minerals to use it.
But, at the end of the day, when you need to figure out what’s going on… nothing beats playing as Terran. When you get solid with Terran, you feel like you should never lose, as long as the game is balanced.
I rarely ever make a lot of observers. They cost too much gas. It takes up robo time, limiting the amount of other robo units you can have. It’s the Toss version of opportunity cost. Yeah, you might have observers to see what’s coming… but you might die cause you don’t have enough “good units” to stop it.
I’ve always thought that simply placing pylons around the map is better than making a lot of observers. Sure, Terran can see when they fly over a pylon, but if it deters them from dropping… I’d probably prefer that than having to deal with the drop in the first place.
Zerg’s vision is just an unprecedented level type thing. There’s nothing fair about Z vs T in that regard. When you get to see nearly the entire map without even having to spend minerals to obtain the vision… how are you supposed to lose to anything? Zerg units need to be weak just to compensate for how broken mass creep is…
Toss’ vision is horrendous. There’s nothing good about it. If my opponent masses observers, I couldn’t care less. Just means he will have fewer immortals and get rolled even harder by colossi. And obs are so easy to pick off, I’ll still snipe them just to add insult to injury.