Sounds like a design problem. A covering of woven UHMW HDPE would make the slides more puncture and slash resistant, and could take the "collect passenger shoes" item off the emergency checklist.
But that would also make the slides more expensive, so it really all depends on what the airline thinks a dead passenger is worth.
Edit: The structural integrity of the slide is provided by pneumatic pressure on a rubber-like material (neoprene?). The thickness of that material could be reduced somewhat if HDPE fibers were added. You're not trying to make the things bulletproof, just shoe-resistant. The end result would be a lighter slide, but it would be an order of magnitude more expensive.
The probability of the slide being used is low. I expect the slight inconvenience of passengers removing their shoes during an emergency doesn't justify the extra weight on the slide.
