For now only phoenix and bear should return for obvious reasons.
But all the other ones? does anyone care?
To answer your question, yes, thousands of players have unfinished evolution buildings. you forget the 99% isn't like you.
You say that universal artifact is too powerful, and then you say only bears and Firebird matter, all others are unimportant.
So, the universal artifact works as long as they don't hand out bear or fire bases to anyone who already has a base.
Remember when we got 2 artefacts in the FA? we instantly went into a "7 is enough mode", so when a while back we had no FA with a artafact of the previous event people where shocked.
Again, 1%er mentality. Thousands of players don't even finish events.
As for FOMO, that'll always exist, and they can simply sell full sets or full evo's including 9 artifacts for $100 like they did before.
Just the other day I was talking to a new player who started around 4 months ago and is already done chapter 12 with all magic buildings and every available Diamond expansion. Easy $5K right there.
Also, the "7 is enough mentality" for artifacts already exists, I'm actually saying it should be harder and there should be incentive to complete 9 paths in the FA instead of 3 for essentially the same prize.
and Finally,
(this is what problem-solving looks like BTW) they could increase the cost of event flags so that "7
isn't enough". Simply make the average number of artifacts won in an event when picking chests lower than 7.
In 5 minutes you could redesign the game so that to evolve a new building would require
- an entire event (for 5 normal artifacts)
- an entire FA of all 9 paths (200 AF)
- all 3 floors of the spire for a month (252 AF)
That leaves 0.5 of a universal artifact leftover after evolving your new building to the max.
As long as each new building is desirable, which isn't hard, players will place and spend.
Might there be freaks in the 1% who don't place
good buildings in order to hoard AF for a future
great building? Maybe, but again solutions are SO simple you're just being silly if you can't see them:
A cap on Artifact Fragments.
The broken rune shards are what inspired Artifact Fragments, and like those, the purpose is to complete unfinished buildings. If we set a cap on how many AF you can have in the bank we limit the loophole abuse attempts pretty easily.