Would a normalized, hashed, protected chainstate reduce miner storage costs?
You don't actually need to commit to the chainstate in blocks - just compute it the normal way, but throw away the block data after validation.

In fact, that's exactly what the pruned mode in Bitcoin Core 0.11 does, and it supports mining.

Storing the hash of the chainstate into blocks does have other advantages, like being able to skip processing historical blocks entirely if you're willing to trust a miner majority to commit to a correct one. However, it comes at a very significant cost for validation, as this hash would have to be recomputed and verified with the entry inside every block.