Historically,the monitoring of the production of resources in the town has caused problems.
The town is pretty cluttered as it is, so am not sure where a bin with a pointer could be placed to show the information you want.
However, isnt it true to say that this information is also actually already there, in the top left hand corner?
All you need do is remember what your capacity level is, (which tends to be far too low, and soon reached) after which there is no production in town.
I do not know how difficult it would be to program all the information in that same box, but would imagine its of low priority, given all the complex things they are trying to get to work.
One problem with automating another thing, in my opinion, takes the some of the human awareness out of the game playing experience.
There are illegal bot scripts that'll farm for you and others that do your tasks from a user-free computer...both clearly a non-play, in my opinion.
We need less of these things, not more :)