The creator of the clan? They can just advertise their clan incorrectly.
1. It's not in their interests to do so. If you have a store that sells clothing for morbidly obese people, you won't get much out of advertising it to skinny people.
2. Clans become what their membership wants them to be. If TRF started advertising itself as a Strategic Clan today, we'd likely be getting a higher proportion of strategic players (relative to diplo players) than we do today and be off the radar for diplo players looking for a Diplo Clan. In the long term, we'd become a more strategic clan than we are right now.
This label system would actually be pretty nice- other games with this functionality allow players to add "tags" to their clans/alliances/groups/whatever. The tags themselves are player-created so they end up being pretty accurate and reflect the sort of filters that the community wants to see.
I think the main flaw with this system is that it requires Fizzer to do something the community wants, which I don't think is very likely to happen.
So really the only fair way to do this is to create a system to participate in, instead of trying to track statistics in any arbitrary manner.
I agree. Something like an automated version of Clan Challenge League would probably be best. You can also weight the templates based on their popularity- e.g., if clans tend to challenge each other more often on EU 3v3 vs Poon Squad Imperium Romanum 8v8, EU 3v3 should be weighted higher. You can adopt the underlying logic of something like Swiss Tournaments to devise a ranking system for each challenge template.
Diplo clans can challenge other diplo clans using whatever template they'd like, and everyone can get some sort of ranking that is easily trackable and part of the game itself.
The issue with that is that there's no concrete way to be "better" at a diplo. I don't think diplo clans need to be in a ranking system like this.
Edited 7/29/2015 20:30:53