Part of the problem with this event - in terms of the cats/grand prizes, is that they've left off a very crucial element from the 'original' FoE version they borrowed this from...
Namely, the 'Spell Books/Creepy Toys' 'bonus' mini quest lines.
As an example, in the FoE version, you could find special items that provided a bonus mini quest. Each quest contained 5 tasks, the first 4 of which gave out 5 event currency, while the final quest offered a minor to moderate reward.
And while yes, it seems like 20 currency per spell book/creepy toy quest line is pitiful, an active player was easily capable of blasting through at least 18-20 of these during the event. (myself, I managed 28, which gave me 20x28 = 560 bonus event currency!)
That's enough extra event currencies to buy 1x 'large' tools pack with some bonus to add onto your daily incident pick-ups.
Secondly, (yes, it gets worse!), in the FoE version, we paid only 395 currency for the large tools pack, and got 20 candles vs. the 18 we get here... so yes, they're also badly gaking all over us in that regard as well.
With very careful use of tools in the original FoE format, it's generally possible to claim 1 grand prize, (and a couple extra cats/light bulbs in FoE), per large tools pack.
So to better balance this event, we need the COMPLETE VERSION of it vs. this nerfed version the devs have gakked out!!