I don’t think this is necessary. This would just make minerals cheaper and worth less. If you want to min-max your mining more, just use tech 2 mining crystals.
I am for this, but IDK about including highsec, L5s are supposed to be a lowsec thing.
Also if they were to do this, I would like them to redo the mining missions as well. Most mining is in barges and the ore is sometimes spawned very far out and you need to slow boat it over there.
Little known fact, but mining missions actually scale very well with more pilots (unlike security missions). If you have an industrial support ship boosting another ship, like a Coveter, you would be mining more than 2 people. Thus be able to complete the mission faster and make more ISK/LP an hour.
More on that here: https://greedygoblin.blogspot.com/2014/05/business-post-mining-mission-farm.html
Also that article was posted before the industrial command change, so it is probably even more profitable now (since they can now use mining drones very efficiently)