computer-fail isn't fun
computer-fail is intended to be shown in error situations, as a light-hearted motif. The point is to try and defuse a potentially frustrating situation by introducing a bit of humour. There are plenty of examples of other products that do this.
The issue with computer-fail is that it's just not fun or light-hearted. This means that when you try and pair it with light hearted text - "oh dear, something has gone wrong" - the experience falls flat. It's like getting a joke wrong - we miss the mark.
This issue is probably partly to do with the fact that the symbolic is generally used at larger sizes, where it appears stark and lacking detail.
A sad computer is actually a decent metaphor, but it needs a bit more interest, detail, and fun. Alternatively, we could think about other characters that could be paired with error text. A quick example that I came up with yesterday was a robot, which could be paired with machine-like text:
We could even take this as far as having graphics for typical types of errors - crash, content not found, failed operation, and so on.