As article submissions are so far and few between, I don’t see much purpose in tiers.
Perhaps you could make it known that shorter articles are welcome. If there got to be more than one article a week, then you could try and cross that bridge. Maybe you could allow O-Nerds or arbs to "tier" the articles themselves by voting on the level of detail/support for each article (1-3).
But like I said, we don’t have that problem (too much content) right now.