[D] Why is protoss doing so bad in the GSL? - Page 97

For early game warp prism drops.

Immortals have 5 range and are slower then marines/zeals they don't "kite". You can do some pickup drop micro vs melee/ground units but all traditional AA units(marines especially w/ stim, hydra on creep, and stalkers[prisms are armored]) do exceeding well vs the low health warp prism which only has 40 shields so regen abuse is minimal. Immortals have long been known as a decent drop unit but only vs structures not workers. Immortals need +2 ups before a pair can one shot Terran workers. As a result immortal drops tend to very little dmg to worker lines as they have low dps vs light units and are to slow to give chase if the workers are moved.

This is the same issue with stalkers, although they are able to give chase to running workers, they have very low dps vs light units and they lack the high dps vs armored that immortals have(i.e. stalkers aren't much of a structural threat).

Zealots have another issue for they actually do decent dps, but since they move slower then workers they effectiveness can be quite easily compromised by the opponent just running the workers around. Zealot drop are quite good if you can manage to "distract" an opponent enough so you hope he doesn't notice. As players get better this becomes far less useful. Including sentries in the drop can make it far more threatening but its also makes the drop far costlier. Any units you warp or bring in beyond the initial 4 will be scuicided, so the risk goes way up on the drop being actually successful(you have to inflict that much more dmg since you have guaranteed yourself losses on your side).

Note to get blink/charge and warp prism drop will push its availability significantly later in the game. Unfortunately the timing works out so that Terrans will have access vikings and/or stimmed marines, Zerg mutas or hydras, and Protoss likely will have collosus while you don't meaning that you trying hard not to die. In typical games, this pretty much means your warp prism drop will be a scuicide run. In order to remedy this you need the warp prism speed upgrade, the time it takes to get this tends to make this a late game drop. Of course late game drop options have been always quite good for Protoss. The problem is precisely that, they are late game so the overall economic and pressure benefits of harass tend to become allot more muted.