So, while I understand the removal of the Moonstone Library from spire (and the subsequent lockdown to one being built in the MA) as a means to keep them and the goods they create from getting out of hand, it has left some issues with new players being able to craft in the same fashion as more established ones, once they too have put in time and effort. Additionally, certain building artifacts are vastly more important to a newly developing city, and others, such as the Valentines Artifact we can currently win, are practically worthless at the start.
To that end, would it not be better to allow players to have some choice in the reward they receive when hitting the slot meant for the Artifact, or previously, the Library parts?
Instead of cycling through artifacts in chronological order and making those who started after the Phoenix and Bear artifacts were listed wait for an entire cycle for them to return, would it not be better to reward a certain amount of a new spire-only currency for the artifact win, which can be used in a store that opens while spire is closed (can use the same button!)? The store could be stocked with a rotating assortment of artifacts, moonstone library set buildings, past event buildings, and possibly even other things able to be won in the spire. Weekly limits could easily be placed on any of the available options, and it should be capable of determining whether someone already has a building - such as part of the Harvest Festival set, if it is decided to offer it in the shop at some point - so as not to allow overflow on buildings not meant to be built more than once.
This would allow for a more controlled growth for new and old cities alike - some may wish to buy more time boosters, others may save their currency to purchase phoenix artifacts, and others still may purchase moonstone library set buildings. It would also allow for different currency amounts to be awarded from an "artifact win" at different levels of the spire, much as the different moonstone library set buildings were previously rewarded at different levels. Additionally, it would allow for additional personal rewards in the form of currency for progress, so even if someone didn't have the luck to hit an "artifact win" over several weeks, they are still getting some currency.
I know I can't speak for everyone, but I'm certain many people would rather require a couple "artifact wins" to purchase something they need or want for their city rather than accumulating more of an artifact when they either already have the building at its maximum level, or have no intention of building it at all.