...the downside of many "improvised" weapons is their reduced accuracy. I would so love the idea of a finely balanced sledgehammer with a reach of 2 and all that mass, swinging at someone's cranium, but 3 accuracy (4 if you add personalised grip) is fairly easy to dodge.
In 3rd ed that was not an issue so titanium baseball bats, sledgehammers, and thrown objects (like a cueball) in the right hands could take an opponent down.