My problem with the system is that it encourages people to just skip all that lower tier ore gear and go straight for titanium/adamantium/frost/forbidden armour, regardless if they're the strongest of hardmode ore sets in theory only, or even just skipping all the mining and getting Spider Armor. As I see it, this system seems to have been thought of as a way to re-introduce the early pre-hardmode experience in early hardmode, where you go underground to explore and mine for ores, climbing up the ore tiers and upgrading your gear.
Which would have been fine, even if I'm not too fond of whole mining experience myself, except that by early hardmode you have many, many good options for gear that don't involve mining ores at all, you can even fish for crates if don't want to break any altars, and there's basically no reward for exploring underground in hardmode, compared to early game where going underground is one of the best options.
My point is that this attempt to replicate the whole early game experience (of exploring the bowels of the earth and mining for resources) in early hardmode just feels way too lackluster as it is.