Luke is an interesting mystic in that he's best when played to full hi-jinx and shenanigans. His stat line for both Mystic and Seeker is mediocre, so you're going to be most successful looking for ways to grab clues from the Dream-Gate that require little or no testing, and using his dippy do dah to avoid monsters and traps, or cause them to fizzle.

Some fun suggestions:

Gate Box + Vantage Point + Seeking Answers combo to pull two clues from a high shroud location with only auto-fail to stop you. With Seeking Answers (2) this can be done in one action. If you can boost the Camera while doing so, awesome! Play Enlightened on this Investigate to turn a card into a charge on anything but auto-fail.

Gate Box + Pathfinder to instantly teleport to any revealed location as a free action. You can set up some serious crazy with Shortcut, 2xPathfinder, and your Gate Box where you can Pathfinder into an unrevealed location, Shortcut into a second (use Shortcut second in case a monster spawns), then Gate Box shenanigans and use the second Pathfinder to pop out wherever with a full turn's worth of actions remaining and two additional revealed locations.

Alyssa Graham + Gate Box + Drawn to the Flame to pull two testless clues from a high shroud location when you find an encounter that can't spawn at your Dream-Gate. If you are the lead investigator, Alyssa can do a lot of work for the team by identifying location attachments, treacheries where X is based on shroud, and irritating no-VP monsters for you to negate. (Just remember to use the Gate Box during upkeep player window!).

Hemispheric Map + Gate Box + Read the Signs for an 11 skill test as long as four locations have been revealed (See Pathfinder/Shortcut above) - another two clues on basically anything but auto-fail. If you're rocking the Camera from earlier as well this could mean even -8 is no biggie.

Working a Hunch basically any time you're at the Dream-Gate and won't be using your once per turn ability on something else.

I have found that when I play Luke my partner is often annoyed that it's STILL MY TURN because I'm doing so many free trigger actions. That's typically the best sign of a successful shenanigan - your game group can't believe you still have actions left.

I am writing my first review here as I want to check that idea:

That card to me could do wonder on Zoey Samaras with a type of deck that wants her to collect most enemies possible, for example with "Let me handle this!", On the Hunt, Taunt (and Upgrade 1/Upgrade 2).

Let's say that in this situation, Zoey gets around 3 enemies on her, attacks a full round, plays Hiding Spot so performing 3 Dodge at once.

The cherry on the cake, she gets automatically engaged again, bringing her 3 resources or 2 resources and 1 test-free damage with Zoey's Cross

And the more enemies she has on her, the merrier!

This card appears to suck really bad in the Innsmouth Conspiracy Campaign. It has mechanics which prevent its use, and then when you want to next use it, you are no longer repurchasing so can't use it then either.

Another enemy signature weakness. Looking at the two elements, the effect and the discard condition, we get:

The effect: Easy to hit, hard to damage, hard for Nathaniel to Evade, hits pretty hard. Normally, this is 3 actions to clear, although you can speed things up with Beat Cop, Counterpunch, or Survival Knife (probably with Bandolier). Guard Dog can also help. Handcuffs shenanigans are also a possibility. This card will pretty much cost you a turn, one way or another, but is rarely a danger to either the scenario or campaign.

The discard condition: Kill Tommy or put the cuffs on him; your choice.

All in all, this is an average signature weakness.

This is a fairly unique trauma signature weakness. Looking at the two elements, the effect and the discard condition, we get:

The effect: You take direct damage and trauma, mental or physical, your pick. Normally, this would be disastrous, but Calvin likes trauma, right up until he doesn't. There is no real mitigation, except not getting trauma outside of this card or, maybe, limiting drawing as much as possible. If the direct damage defeats you, you are getting 2 trauma, and once Calvin hits 6 trauma of either sort, you are out of the campaign. If you can get down Five of Pentacles, Until the End of Time, or any of the other soak assets, you can keep going with even very high trauma, but, if you draw this every scenario, you will be on very tight margins.

The discard condition: One and done. You take your trauma, and you take your chances.

All in all, this is an average signature weakness. It's managable but can end a campaign.