This unit, the Chinese Imperial official is a niche unit that does have some useful functionalities.
The 20% increase in drop off is extremely functional throughout the game and once you have 6 or more villagers utilizing that dropped off point you’ll eventually pay for the original cost of the official and begin to gain effectively a more productive villager.
The second ability that is amazing is the ability to speed up the production capacities of buildings, currently 150%. Since the IO costs 150 food it is a cheaper military building both because food gathers faster than wood AND 150% production equates to 1.5 additional barracks (for example).
Now the last functionality of the IO needs to be severely improved!!! The ability to collect taxes!! The gimmick of having to collect the taxes instead of it being directly being deposited into your stockpile diminishes the perk that each villager drops off 1 extra resource (2 if inside the 100% tax buff). It is further diminished by the fact that each taxable location gets a 15 seconds timeout where no more taxes can be collected? Still worse than that is that the IO does NOOOOOTTTTT prioritize going to the highest tax pool FIRST???
These are my suggestions on how to fix the tax collecting clunkiness:
Change the IO to prioritize the HIGHEST and closest taxable location.
Next reduce the cooldown after tax collection.
And second to finally remove the necessity of the IO having to return to the TC in order to drop off tax. Instead replace that need with a short animation of something like the IO putting the coins in his purse. This could greatly increase the efficiency and the management of the official.
Finally introduce an Imperial upgrade (maybe via dynasty) that allows the tax to be auto collected at set intervals. Like every 30 seconds poll all locations and collect them all simultaneously.
As it stands alternating between collecting taxes when optimal vs applying the 20% eco drop off and being aware of the 15s coolldown per location, is extremely TAXING on the gamer!!! Other faction with gold gimmick/eco boosts are seemless and even some on efficient autopilot!!! (HRE prelate and relics; Rus bounty system; and English gold trickle)
EDIT
A little more into the mechanics of the IO. Since the IO can only be que from the TC making each IO displaces your TC from otherwise making a villager. Furthermore the IO cost 150 food compared to 50 food for a standard villager. So basically IF WE’RE TALKING ONLY ECONOMICS the IO has to more than displace the economic generation of 1 villager in order to eventually pay for the 100 food extra it costs AND has to continue to outproduce 1 villager in order to have been worth the investment.
Using the Standard gather rate of a villager of 40 resources per minute and that the standard drop off time of a villager is about 15 seconds means IFF you’re ONLY collecting gold with your IO you need 11+ villagers working in order to JUST collect taxes and have that IO eventually be a more efficient villager.
Alternatively if you JUST want to provide the 20% increase drop off then you need 6+ villagers to eventually pay for the IO extra one food cost over a standard villager then begin to be a more efficient villager.
At pro micro (aka watch Marine Lord do it all the time), you can maximize the IO’s output early game by doing BOTH the 20% drop-off and in between drop offs collect the taxes. Ideally with just 7 villagers and the ability to just collect 20 tax you can have your IO be worth 2.1 villagers!! This means you’d pay off the IO 100 food additional cost in 2 and a half minutes and continue to have 2 villagers worth after that (assuming you can keep up the micro).