Your proposal completely removes that check on miners' power
Ok. You just misunderstood me. I've changed "rejected blocks potentially could be included" to "temporary rejected blocks ..." in my first post.
Actually my solution doesn't solve the 51% attack problem. But of course the best chain is selected only when it meets the consensus rules.
The point of running a full node is to ensure that miners follow the consensus rules, not just to have the entire blockchain.
I don't think that full nodes have any significant power. But they can try to continue to reject undesirable blocks more than after 2-3 following blocks.