My understanding is that the "Clan Competition" is like a ladder system, with Tier 1 being the highest and best tier. If you are not fighting very hard as a clan, you will drop to a lower tier at the end of the round. If you are doing really well, you will go up to the next tier at the end of the round. Right now, I'm guessing that the top tiers are mostly filled with clans that were lucky to start playing first, and so they were just given a spot in the highest tier with available space. So clans who got stuck in Tier 10 will now have to do a lot of work to get up to, say, Tier 6, and it will take them a minimum of 4 rounds to do it.

So at this point I'm guessing that a clan's position in the tier's doesn't really tell us much about their skill or level of activity. But in 6 months or a year, I expect that all the best and most active clans will have clawed their way up to the highest tiers.