I disagree, for two reasons. (Actually, there's a third, that this sounds like "standardized testing", but let's not dwell on why I think that's a flawed notion as well.)

First, I think people place too much emphasis on XP as it is, and this would make it worse. Don't lose sight of the fact that XP is just a number in a database, a figment of vroom's imagination. As he himself stated, a million XP and 25 cents will buy you a cup of coffee. (OK, maybe a $1.40 at Starbucks. ;-) XP says nothing about Perl coding skills, or general knowledge, or whether you're a worthy person.

Second, the idea that you must perform a task or cross a gauntlet to "advance" is, IMHO, counter to one of this site's main strengths: voluntary participation. I come here to ask and answer questions, and participate in occasional chit-chat, as my time allows. I'd hate for it to become a race or proving ground.

Personally, I think the existing voting/experience system works really well. There have been many suggestions for changes, but I haven't found any of them convincing.