from my perspective:
the trade-off, do stuff with the main production: is quite okay, for not needing to set up these pesky small buildings.
but what annoyed me so much was: I got the 3 toolboxes-quest 3 times in a row. and I have just 5 magical workshops. essentially, that crippled my supplies-production. and a FS-member had that issue with 3 scouts in a row. which made her really unhappy.
so, the event just needs a few adjustments:
1. scouting requires us to wait several days, not funny.
2. toolboxes with the main production drains every bit of fun from the event.
3. a randomizer, that allows several times the same quest, that makes sure, that the fun will never come back.
4. maybe think about something for those with magical workshops. count stuff twice?
solve those 4 issues (shouldn't be too hard), and you are good to go.
(EDIT: by the way, all workshops were earned by bugreports, chapter-diamonds, spire or wishing-wells)
EDIT2: in total, this quest-system is a step forward, no more silly upgrade 4 buildings to lvl 4, no more 10 mini-workshops with toolboxes, etc, and no frustration with accidentally harvesting stuff that would've be needed 3 quests later. you got rid of quite some unfunny quests.
EDIT3: yes I know, since many quests demand uneven numbers of stuff, like 5 toolboxes, doubling the output for magical workshops would mean, that there need to be 3 done (because 2 is not enough). still a valuable trade off.