I can understand the frustration of those who invest a lot of time and Gems on this event. I uselessly spent some dozens of Gems, myself. But for my part, I know I would be really more desapointing to waste Gems and not finish the quest. In that case, the spent would really be for nothing. So I don't complain about this update and say a big thank you to TL to listen to us (for once) and fix this undoable quest problem.
Tips for futur quests: You may already do this but it doesn't cost anything to remind it: for those who don't know what to do with their cottages and farms surplus, keep at least 10 of each (on the map or in the inventory, it doesn't matter), espacially those which are leveled up. That what I did last time we had to built lot of those building and it really help now.