So the upgrade to the Thompson has not generated as much buzz as the version, which doesn't surprise me too much. For 3xp, it drops a resource in cost and gains a niche but powerful oversucceed effect. Altogether not mind blowing.
This card is very interesting to me, not necessarily because of its power or interactions in the game right now but because of the sort of scenario it seems to be designed to handle. At the moment, we dont have a Rogue with a better stat than 3. This means that against moderate to high fight enemies its going to be pretty tough to oversucceed enough to get the benefit. If you're engaged with two 3 fight enemies then you need to hit 6 in order to get the action compression from the Thompson. This means you'll probably want to be pushing your initial value up to 9, a full 4 points over the bonus provided by the gun itself. I think this high cost to using the gun in this manner, even for just medium fight enemies, relegates this sort of plan to a desperation manoeuvrer. Where the gun does shine however is in situations with multiple low fight enemies, or at a push ones with combinations of low and medium fight. The Secret Name comes to mind as a scenario where I imagine this card would do a lot of work.
One powerful upside to consider for this card is that the second enemy you choose doesnt have to be engaged with you. This makes it particularly good for dealing with, say, the awful bastard birds. Unfortunately its usefulness for dealing aloof enemies other than the birds is a little limited again by the earlier point about Rogue values. A lot of the aloof enemies that you'd be hoping to use this against aren't slouches when it comes to combat either, so the Thompson is not going to be a reliable way to handle them for the most part. Also, for this plan to even be possible you need to be engaged with another enemy at the same location, which further limits is application.
The resource discount is significant, 6 down to 5 means that this can be played turn 1 without having to waste an action gaining resources, which is always a plus. This same discount was worth 1xp on Leo De Luca so I dont think I'd spend 3 for this benefit alone, but it does sweeten the deal somewhat.
In terms of investigators that can make use of this, "Skids" O'Toole is the archetypal "combat rogue", but then he has access to the .45 Automatic which does a large percentage of the work of the Thompson while leaving a hand and an xp free for Lockpicks. Jenny Barnes doesn't have a lot of better options for weapons, so I can imagine it being a reasonable fit for a Jenny deck that's not interested in Lupara. Perhaps a Jenny deck that's looking to be a dedicated fighter and so doesn't want to be limited to single turns of effectiveness with Sleight of Hand. As for the third 3 Rogue, Finn Edwards: both version of the Thomspon are actually Illicit. This means that the version of the Thompson has to compete with the much flashier one. I dont think the Guardian version is always better, but refunding its resource cost is a real bonus for a Rogue that cant take Hot Streak. That's assuming Finn wants either of them of course, which is a little doubtful given that he is the poster boy for Lockpicks and cant take Bandolier.
All in all, a pretty interesting option that opens a little more space in the rogue weapon pool, but one that I thing struggles to find a home among the investigators we currently have. I think when a 4 rogue who can more reliably trigger the bonus effect is released it may be worth revisiting this card. Either that, or when we have a cycle focused more on swarms of enemies.