I suggest we have more middle tier curiosities and have your character get 'bored' of the same curiosity after studying it, can a curiosity get a negative multiplier for chaining the same one? And let the curiosity reset or decrease after a set amount of time, maybe off of the duration to complete
Say i have 10 mirkwood offerings and after studying 2, i have a 80% multiplier for mirkwoods. After 20% of the time to study this drops a notch. So after 24 minutes I am back to 100% for mirkwood offerings. An alternative would be to have the multiplier affect the exp cost of the curiosity.
As for how strong of a multiplier or how fast it goes away is up to Jorb and Loftar but i would suggest making it a max of 50% with 5 or 10 'notches'.
This is to deter botting curiosities and make villages break up the pattern or daily chores
-Bots will still be a problem as I would simply make a bot load a line up of curiosities instead of simply replacing. I'm too lazy to learn to make a bot/custom client but this is how I would do it
-Villages will still make a pattern but there will be a 'rotation' instead of the constant same thing
-Also may cause confusion to new players if not properly explained, maybe after quests are added?