Yeah, and that has another problem: developer who code fast but don't think things through would have plenty of issues opened against their code. They would probably be fixing them as well so their close count would be much higher than for a programmer that made the right choices to begin with.

You could then go with features only tickets but those vary in size and complexity. Now, if we would put complexity as a measure (on which the team of developers should agree) and then measure the number of issues on that implementation we might get a better measure of that person's contribution.

That said, once that would be in place, even that can be gamed.

I think there is no silver bullet here, as much as we would like it to exist.