EPT![[image loading]](http://i.imgur.com/Nijc1VB.png?1)
Starcraft 2 brought many changes. At the end of the day, the biggest change has to be the dynamic of the Protoss race that have brought the most design troubles. It can be summed up in reaction to a simple thing:
![[image loading]](http://wiki.teamliquid.net/starcraft/images/c/cb/Reaver.png)
In the primodial time of Starcraft 1, units were designed more on aesthestics than by mechanics, as most of the latter is accidental, with unintended features like moving shot or glitchy movement and glitchy shots. In this environment, the protoss ended up with very clumsy core units, in the dragoon, reaver and templar.
NEVER AGAIN! The Blizzard Design team have decided that the advanced alien race shall never suffer the indignity of clumsiness.
Protoss shall be one of super agility Protoss should always have tools to position units very well tactically on the fly.
We can see this in all aspects of its design. Warp in, Charge, blink, cliff walk, moving shot, mass recall, independent flying mothership core as early "defense," large selection in airforce. More ideas alone the same line was tried, like phase cannon (moving photon cannon), and amulet templar warp in. The 9 range force field and combined with immortal range buff also resulted in even better positioning.
This is on top of many engine improvement in unit packing, pathfinding, selection and smart casting.
All this is not without effect on the larger game. The biggest one is the evaporation of defender's advantage and deathballs. Now the effects of warp-in has been discussed to the death, I will talk about the tactical side.
The more difficult it is to move units into effective position, the greater defender's advantage. Agility removes defender's advantage. After all, the defender does not need to move. A reaver/dragoon army is 100% effective when prepositioned in a concave around a defended point, but is horrible if it has to charge a small choke under fire. While controlling 2 reavers on the attack with a shuttle is not too hard, controlling 6 becomes very difficult and just compare that with A-moving Colossi.
Now, the Terran and Zerg army had strong defender's advantage even without super clumsy units like the dragoon because they had other limitations. Tanks aside, Terran are glass cannons whose units can die (to AoE) before a shot is fired, while Zerg depends strongly on melee and short ranged units. These features remain in SC2 with some additions like creep while the protoss changed the most, removing most positional limitations to attack.
Conclusion
There has been a lot of talk about tank-mech TvP that conspicuously lack discussion of the protoss which is designed as the inverse of mech with massive tactical agility everywhere and weak (pre)positioning based unit or mechanics.
Bringing back big fat clumsy units might not be best way, but that does not mean the protoss must equalize attack and defense. Take the force field for example, if it had 5 range instead of 9, it would be a defense only spell as opposed to a army killer one.
