if somebody remember how top clans got their rank i will explain:

90% times top clans were having clan wars with fresh just formed clans to earn points to rank up.

with this system you would not be able to farm clan war points by waging wars with naab clans, but will had to fight with clans more or less equal to you.

also don't worry about "what if all clans from my group will become inactive"
all points from clan are scaling according to % of activity, so basicly if clan have only 1 person active from 10 they will have 10% of ther actual points.

by this only active clans that wage wars and/or participate in events will stay on top. (as it should be)