But what you posted DIDN'T maintain decentralization, it simply redefined a non-mining full node to be lesser than in a non-sharded network.
Less storage and less bandwidth than now but control of emission is still maintained.
That didn't make any sense.
Think of these shards as cloned altcoins with shared (and very high) hashrate.
You said that miners/stakers are required to have all the shards. That is NOT sharding, and it makes a full node lesser than what it is in a non-sharded network.