Add 1-2 Iron bases yourself and you will avoid the stackers
I promise you, only 1 iron age base is enough in 30x30 or 25vs25 match ups - at least it is for us as we consist mostly of industrial age players.
We were like you, facing stacker after stacker so we dropped medal requirement to 200 and let in a few Iron Age Bases. Now we bring 1 or 2 into every war and we do not see any stackers in our match ups. We only meet alliance fairly close to our level, meaning 1/4 global, 1/2 Industrial and the rest EA to gunpowder.
Only "problem" we have now is that we feel that we put a lot of work into trying to train/improve our Iron Age players, who very often are players who are just trying out the game, and hence become inactive very fast. So we kick these players constantly to get in new ones... (Automatic kick if inactive for more than 3 days without giving a reason in the chat before going inactive).
The good thing about this "micro-stacking" is that if everyone does it, it means that it will be easy for new players to join an experienced alliance and learn from them, and in the end the serious stackers with 4-8 lv198 bases and 4-8 inactive Iron age bases will only face each other
Removing stacking completely is "impossible" because it will change the game and WW completely - making it hard for new players to get into a good alliance and grow... Because who of the top alliances would accept an Iron age base if they could have only Industrial and global? Very few that is... making the entry into the game that much harder and boring for new players.
Only possible solution to stacking is to divide the alliance match up into brackets. Matching e.g. the top 1/3, middle 1/3 and bottom 1/3, in stead of matching the whole alliance as they seem to be doing now.