
I was trying to come up with a use for this card, and I'm got to say I'm pretty much stumped. Maybe I'm missing something. But given that this card cannot stack with a weapon, it doesn't seem good for much.
About the only use I found is that this card is good against Rats (since reducing the test difficulty to 0 means almost a guaranteed success.) Solo Wendy can actually find Rats pretty irritating on high levels, so maybe there. Rats are generally not a card I worry about countering when I'm designing a deck, though.
For most investigators, there's the risk that Improvised Weapon gets stuck in your hand as a really weak event (attacking for 1 damage is not very good) that has no skill icons. That's not great.
For all the investigators with high Fight and access to Improvised Weapon, like Mark or Yorick, this card seems clearly inferior to simply fighting with a weapon, and therefore not really worth the deck space.
Wendy and Pete, of course, can fodder off Improvised Weapon to their special abilities and then play the more powerful version from their discard pile. Which sounds great... except that they have 1 and 2 base Combat. They can't hit with this at all, not unless they're playing an Easy or they're attacking a 1-Fight monster. And there are just not enough of those to justify this card, I think.
However, I think this could be interesting in the future if we get more effects that can reduce monster Fight and stack with this. Quasi-guaranteed successes against 2 or 3 Fight monsters would be really useful.