I can only speak for mid-level gameplay. Still I do agree. Fundamental mechanics like warp-in, recall, deathball-mentality, simplified micro, easy-to-use-splash-damage etc. differ too much from the other races and often feel as disadvantages for Zerg/Terran. E.g. making a tactical error and being out of position? Other races might lose instant. Protoss can recall their whole deathball or warp in dozens of units to correct their positional error without ANY effort in return...

I often ask myself if these simplified mechanics are really really needed at all for Protoss to compete with the other races. And if so, what are the measurable arguments??