Why don't you have a general ideas thread just to gather propositions for PH features?

Here's mine:

Money (un)happiness, money sinks:

People should get unhappy if the player hoards too much money. Every e.g. 100k on bank should give a penalty on happiness or something because the mayor is 'not doing anything'. It should be possible to overbudget services further away than the default values to prevent hoarding too much money.