Dealing with resource shortages

In an earlier iteration of my game, if you don't have enough money to pay the maintenance cost, then the "End Turn" button is greyed out.  However, during testing of game, I found this to be very annoying.  This was before the resource overhaul.  So I've been thinking of ways to punish the player for not having sufficient resources that isn't annoying.

I would like your feedback on the following idea.  This is partially inspired by MoO 1's subtle handling of maintenance.

There are three layers of economy in this game: Planet, System, and Empire.  Planets consume resources first, then system, then finally empire.  If a planet do not have sufficient resources to pay the maintenance or consumption requirements of a region, then its efficiency is reduced to the percentage of available resources vs required resources.

For example, if a region with two buildings requires 10 BC total, (with one building requiring 10 BC in maintenance, and the other building don't require maintenance, neither do the region), and produces 20 Industry.  The region normally give 10 Industry, and the first building gives 2, but the second gives 8 (this one is the same one that requires 10 BC maintenance).  If you only have 5 BC available, then the region will produce 16 industry because the region and first building don't require BC, but the second building does, and it gets only 50% of required resource, so its output is 50% as a result.

For the System level, resources are consumed in projects, so it directly affects the length of the project's completion.

For the Empire level, the only things that require resources are trading, ships, and leaders.  Let's say that you've set up an trade agreement to trade 20 research points for 30 BC.  Then on one turn you only have 10 research points (Trading is deducted first before projects deducts theirs), so as a result, you only get 15 BC. That way, you can set the maximum amount of what you want to trade, and if you suffer shortages, it automatically adjust the trade.

For ships, they also suffer penalties.  An example: if they only get 50% of their upkeep cost, then they move at 50% speed both in galaxy and combat, and perform at 50% efficiency during combat, by halving the weapon damages and movement speed and other stuff.  Some ships may not suffer penalties if they have sufficient resources (a ship with an exotic drive may be suffering from penalty of lack of exotic fuel, while others don't).

Leaders likewise reduce their performance, and increases the chance of them quitting.

With this system, if you cripple an empire's economy, you cripple basically everything else.  So spies will play a bigger role than in traditional 4X games with this system.  A spy may destroy or steal resources from another empire, destroy ships, destroy infrastructure, steal technologies, frame other races, etc.  My goal is to have different ways of playing the game to be rougly equally balanced.  If you're a spy race, you can destroy empires via spying (usually not possible in other 4X games).  If you're a trader race, you can drive other empires to poverty via unfair trading (if they're really desperate for a certain resource, you can charge exorbitant rates for it) and monopolizing resources.  If you're a warmonger race, you can capture other planets and do generic war stuff to exterminate other empires.

This system will be simple enough for casual players to easily learn, but will require a lot of practice to master.  I'm seriously considering working on the strength of my new economy system and add a lot of diverse resources to enhance the economy factor.  For example, instead of having abstract fuel ranges, you actually have to mine those fuels and supply your ships with those fuels (such as "Dilithium Crystals" or Plutonium for nuclear engines, etc).  Researching new engine types will allow you to use different fuels.  Maybe your empire only have access to a certain fuel, so you'll want to enhance your engines that use that fuel to be more faster and efficient.  So yes, there will be wars over resources, and trading for resources.  Same for weapons, buildings, research, etc.  Some weapons may require exotic materials that are available in limited quantities, and you can only build 1 or 2 ships at a time.

Your technologies will be determined by what resources you have access to.  While you may unlock technologies for research, you can't research them unless you have the appropriate resources.  This is where spying and trading comes in.

So, what do you think of this?  It will balance out the races, so even if a race is very good at researching, they'll be helpless if they don't have access to resources, and may need to trade research points for those resources!  Trading races will actually be more powerful in that they can use economy to their advantage, instead of generic "+10 BC in Trading".