Somebody's going to drop. The average win rate will always be 50/50 no matter what. If some are above that, just as many will be below that. That's the way it is now, that's the way it will always be so long as every battle has one winner and one loser.
You may be able to win all offense battles, that's 39 per day for free. But the players that spend to buy tokens will be able to play 40 matches every hour, more if they spend for refreshes as well, gaining severaal tiers in a day. Players could move from S1 to G1 in a week easily. And that much movement up will have a corresponding movement down.
That downward movement may be spread over more players, but that just means more players will be negatively affected, just to a lesser degree.
You may not drop a tier every day. But every week you'll drop unless you start playing more offense battles than defense.
So how do I make sure I don't drop a tier immediatly after reset? I make sure I'm the first one up and I easily beat the first 10 opponents on the list. I just got a lot of medals and knocked 10 players down a tier. If 100 players do the same thing, then 1000 players wake up an hour later and find they've dropped a tier.
So let's say we agree to put up a defense just around reset, then take it down. I already do that, no problem for me. But how does that help players that are in a tier artifically only because they beat a bunch of 1 champ defenses? They are going to have to wait 1/2 a day till everyone takes down their defense. By then they will most likely have been hit on defense a few times.
I could be wrong, but I don't see it. It's a moot point anyway. No hope of 1000s of raiders agreeing that Wednesday is the middle of the week, much less to try this.