Self-maintained groups and incentives based on performance. It would be interesting to adopt this in the tech area: the amount and quality of your unit tests means you get paid more. You can also do code analysis: look at branching factors; code duplication; runtime performance; etc This might be hard to implement in a company setting; but it may be easier to apply with contracting work.
How do you quantify whether someone is solving a problem the wrong way, just because that way will score better on the metrics?
Just make the metric to be money and it will work. It takes a big re-org to put the tech tasks in terms of profits, but it's possible to a big extent. Break the software into ownership domains that are peer reviewed and monitored on how much money they contribute. Then sell the software in packages assembled by customers or your internal marketing and solution consultants. This way you encourage the developers to talk to the customers or marketing to collect input and requirements what needs to be done next. Developer can choose to work on something profitable or something cool and obscure, but make no money on it, it's his choice. In both cases, the developer is motivated to be efficient.