Gankalicious isn't all that happy with the Clan Wars endgame of World of Tanks. The endgame is dominated by level 9 and 10 tanks, and his favorite tank is level 5. The high-level tanks also dominate the organized PvP tank company against tank company, where each side can bring 90 levels worth of tanks: 9 level 10 tanks easily beat 15 level 6 tanks. Thus Gankalicious proposes a second tier of Clan Wars with a level cap of 5. I think the level cap would be a good idea, but to keep the spread smaller I'd either make one alternative Clan Wars with a level cap of 7, or two with level caps of 6 and 8. With progressively lower rewards, of course.
Now you need to remember the peculiarities of World of Tanks compared to let's say World of Warcraft. World of Warcraft for historical reasons has raid dungeons not just at the level cap of 85, but also at 60, 70, and 80. But in WoW leveling is fast, and raiding is slow, so unless you'd turn off xp gain, you couldn't raid the level 60 dungeons without quickly outleveling them. In World of Tanks your tanks don't actually gain levels, you gain xp which allows you to unlock the next level of tank. Thus even somebody with a level 10 tank will still have lower level tanks in his garage. Having a lower level "endgame" thus doesn't exclude those who already advanced further.
As in World of Tanks leveling is slow, and the endgame is fast, a lower tier of Clan Wars would make sense. It would give clans an opportunity to play together without having to exclude those who are not yet level 9 or 10. Right now the only clan activity which makes sense for all but the top levels is doing random battles in platoons of 3.
Of course Wargaming.net might prefer to leave Clan Wars to the highest level of tanks for financial reasons. As mentioned before, while World of Tanks is really free to play at the lower levels, it becomes increasingly difficult to get to the higher levels without paying for a subscription or gold tank for farming. Thus the old mindset of "the game begins at the endgame" is a source of income for the game company in this case. Otherwise people might notice that you get pretty much the same content at level 3 that you get at level 10, and the game is equally fun at all levels.