The Masteria’s Legacy Set was advertised as being powerful, and upon initial release it was noticeably strong with a 10% Critical Damage boost in the set
bonus, as many players discovered via the use of Pet Item Ignore. However, this boost was nerfed to 5% Critical Rate, and players soon discovered that Shadowknight Coins were a necessity to Star Force this accessory set, at a rate of 5n + 5 (i.e. 0->1 requires 5 coins, 1->2 requires 10 coins, 2->3 requires 15 coins, and so on).
The wording "upon initial release" isn't quite accurate.
As you may recall, the release of the Phantom Forest revamp was delayed due to bugs, and at first we only got the NLC revamp. However, the data for Phantom Forest was mostly included in that patch, and so you are right that people learned of the 10% crit damage set bonus in the upcoming set, and got excited for it, even though the individual items in it were unexceptional.
When Phantom Forest was finally released, it was with the crit rate set bonus, which instantly made the whole thing not worth breaking other accessory sets for. Only the ring remained viable, because we have 4 slots for rings, and this one is high enough level to get 22 stars. But the catch is that it needs to have high star force to be better than other rings that are much easier to obtain. So the coin requirements for star force killed that last bit of desirability for any part of the set.
Before the revamp, Masteria was "dead" and "people only went there to craft Balanced Fury and Crystal Ilbi throwing stars, or for anvil-fodder novelty equips". And now, after Nexon invested a lot of developer time to revamp it, and suffered much backlash from players, both for nostalgia reasons and for objective game design reasons (like your well thought out post), Masteria is still dead and people still only go there for those throwing stars. Some of the novelty equips are still obtainable from the revamped Masteria, but some joined the ones lost in the 2016 Masteria updates, in the great bit-bucket in the sky. It'd be funny if it weren't so sad. (less)
No, it's more like an acceleration lane for people who are too overwhelmed by Maplestory's complexity.
I don't think any other game does that. Seems way too complex for the developers to maintain these multiple "instances", each at a different stage of the game's history.
Hellome666, just imagine you are starting up a game you've never played before, and learn it as you go. What you remember from back in Beta or whenever you last played, is largely irrelevant by now. You left the game, and maybe you regret not experiencing each update as it came, but it's not practical to create a personal environment for each person to feel like they played through the past 15 years. (less)