Unfortunately that is not a viable solution. Many people invest to get to the top, and to then move them against more difficult players (or more invested) would devalue their investment.
They have also said they do not have the tools to mix merge shards.
There are also other reasons a solution like this doesnt work,
- where do they get placed in the "new shard"
- it would actually make chatting more effective and necessary as you dont want to step on the toe of people with other POs. This is the main reason for most chats.
- what keeps someone from losing to get pushed to an easy shard and just dropping back once every few days to keep the easy shard for top PO most days