I think it's mostly a fact that many of the protoss units do not seem to have a defined role (especially the new adept and disruptor). To begin, the concept of the adept feels a bit flawed in its current form. It appears as if the design choices are pushing the adept in the direction of tanking damage (with the shield upgrade and base statistics). However, the shield upgrade doesn't really mesh with the psionic transfer ability which is good for avoiding damage and flanking enemies. It might be interesting to try changes which push adept more in the direction of fighting small drops (maybe with the help of stalkers) or blocking enemy escape routes. This would provide protoss with a greater ability to have a mobile force to fight off terran drops and zerg runbys. It would also make the protoss army less about "1aing" which has been a huge concern by many members of the community.

The disruptor is also probably what many people were referring to as "gimmicky". It still seems a bit too expensive for the action it performs. It can be avoided fairly easily still, requires a huge amount of micro in addition to normal army micro, and has huge costs if it doesn't land a good hit (given how fast the battles occur in starcraft). Protoss also doesn't really have a good way to hold a position to utilize how long the attack takes to detonate.

Finally, I believe that the colossus and tempest still have some identity issues too, but many other people have already addressed these units in previous posts.

I think it might be worthwhile to attempt some radical changes to protoss units while we are still in the early phases of beta. This way we can create a defined role for the protoss units before spending too much time attempting to balance the units.