I'll just list the top 10 (not in order) without explanation. These are for healthy committees whose delegates are from basically aligned organizations that are not trying to actively destroy each other, and with the committee NOT having made its own self-perpetuation Goal #1.

In other words, these are the failure modes of the best-case scenario, when a committee is functioning as well as it can:

1. Featuritis
2. Late-to-market
3. Faster horse
4. Me-too design
5. One-size-fits-all design
6. Excessively data-driven
7. Outsourcing
8. Style over substance
9. Cost spiraling
10. Divide-and-conquer conservatism

I'll leave it as a homework exercise for anyone interested in figuring out why these happen and how exactly they follow from more fundamental dynamics such as assumed consensus, groupthink, lemming effects, bell-the-cat effects, and so forth.

Remember, these are for healthy committees.

Unhealthy committees: every good example can be made into an entire movie, there's so much going on. I'll give you just 2 examples to illustrate the richness of the phenomenology:

1. Poison-pill design (somebody introducing a Trojan feature designed to make the thing fail; happens more often than people admit)
2. Design by parasite (somebody optimizing the design for a different objective than the nominal one, like a powerful engine supplier convincing an airplane company to design its new plane around the engine it wants to sell, rather than the engine that's right for the job). In extreme cases, design by parasite becomes design by cancer cell.

And finally, to bring some balance to the question, design by individuals is not immune to pathologies. Consider the story of King Gustav and the Vasa.

http://en.wikipedia.org/wiki/Vas...

This disaster could have been prevented by committee.