There are absolutely spoilers for a minor quest in this post. Read at your own risk.
Wasn't going to put up another suggestion tonight, but that was before I died twenty times on Silent Isle. I'm sure it's been mentioned before, but the doppelgangers really need to be toned down. As it currently stands, the quest is almost impossible to complete for a PC that doesn't have Thought Control.
Given the placement of moderately difficult enemies (Rathound Alphas and Psi-Beetles), the player can't rush to pick up the Lost Cargo on the northern shore. In the time it takes to maneuver and fight through, at minimum, two packs of Psi-Beetles, the player is set upon by the doppelgangers.
As they currently are, the invincible doppelgangers can easily outrun the player and still inflict three unavoidable electrical attacks that cause an average of 10-15 damage per strike (or upwards of 25 on a crit). The doppelganger fades after three or four turns, but that still gives them time to inflict an average of roughly 100-150 damage to the player before they vanish - more than a single Health Hypo can heal. Then, before the cooldown on the Hypo is even finished, another Doppelganger will appear to finish the job.
I can understand the presence of the Doppelgangers to protect the Monolith at the center of the island, given the potential power of the Bi-Location ability, but they're a bit too daunting for the cargo recovery. They either need to be toned down (maybe a longer cooldown between Doppelganger appearances?), or the cargo needs to be placed closer to the zone entry point for faster recovery.
At the moment, 'in and out' isn't a very reliable strategy, because the Doppelgangers will swarm the player to death before they can escape.
EDIT - I managed to push my Gunner/Trapper through the quest eventually by using hit and run tactics. I ran in, killed a group of enemies, then ran away (ie, left the island entirely) to let the 'Strange Feeling' debuff fade (and to let the cooldown on the Health Hypos finish). It took a total of five trips and twelve Hypos (plus two bandages, which were inconsequential) to kill the Rathound pack, and two of the Psi-Beetle groups. I think I was attacked by roughly eight Doppelgangers during that time.