Just my 2 cents:
The only two things which really demotivate us players are
1) loosing to cheat hacker alliances in wars and
2) loosing silly amount of glory to top alliances which leave their original alliance on the top of leaderboard because they want to take bigger amount of glory from other alliances.
What is demotivating for you might be demotivating for the others.
Now when we are having at least one cheater alliance in the top 20 and NEXON is doing nothing to roll back or sanction them it might be demotivating for the top alliances to loose silly amount of glory to them.
Now when the fundamentals of the game are changing and everyone needs to adapt and many top players are retiring as a result of that it might be demotivating for the top alliances to loose silly amount of glory because of these circumstances.
Now when the CWC tournament is having its final round and many top players are swapping alliances because of that it might be demotivating for the top alliances to loose silly amount of glory because of their top guns are not in the war.
So I have a sort of an understanding for the top teams to discontinue their progress with a top rank alliance, and please don't look at the things only from your perspective.
Now back to the proposed solution:
A meaningful solution to somehow still please the player base - in my opinion - is to introduce a "seasonal leader-board" for alliances (while maintaining the current all time leader-board)
I believe, that whatever rule you'd use to sanction the alliances for not warring is just plain silly - there will be always some solution to outfox it... And on the other side this all time leader-board is a reflection of the efforts of too many players....
So back to the suggestion: The seasonal leader-board should be started (re-initiated) every 2nd (3rd) month with the half of the glory points of the alliances from the last season's seasonal leader-board capped from the bottom with 12k glory points.
Each war would have different glory point rewards for the seasonal and for the all time leader-board.
The rest of the details could be clarified inside the dev team, I'm sure....