1) Why does Ethereum store data in 32byte chunks? I don't suppose this to be some backward-compatibility left-over; is it? We could store data in variable length fields as well.
2)I don't think optimization is the case as we are already wasting over 32bytes (32bytes for the hash which constitutes the path + Merkle Trie node's-metadata) as an access key to each such field (the path from Data Trie root to each variable).
3) any notes on how the compiler computes the access key for each variable?
4) I'm quite new to Ethereum, is there any economic incentive to remove the previously occupied data?