I don't think someone has to collect a very high XP level before he is listened to. I know that I personally have already memorized a couple names I see regularly and see regular competent replies from. The 30 posts I saw may be their first 30 or may be their post #2984-#3014, I couldn't care less.

And the problem you see with good ideas being stiffled, I don't. Traditions become traditions because they're good practice. You can't easily question them without high competence, and personally I found whenever I questioned good traditions, my conclusions where that they are there for good reason. On the other hand, if someone has the competence to successfully question established "good practice", that competence will stand out in general.

Without being able to back it up with too much experience (pun intended), I'd say the XP system works - so long as you don't use it as basis to judge the merit of people's contributions.