Karmawhoring, while fun for a while, tends to lead one into... non-optimal directions.

Non optimal. It can't be unless somehow max-karma happens to coincide with whatever other maxima is being searched for. But it is also unlikely to be net detrimental or a sufficient deviation from optimal to be worth focussing on as a problem.

I would consider the size of the replies thread (which is visible, though not as obvious as karma) to be a better metric of readership and impact.

That's a better metric of controversy than impact. It is a reasonable indicator of readership.