Manpower garrison computation change

Premise: Change how Manpower garrison amount is computed.

Since its very easy to successfully invade enemy controlled planets, specially late game, because fleets tend to carry lots of manpower with utility modules, and the player can easily just spam fleets full of invader ships, it is better to change the formula that dictates how much a planet can garrison. Instead of improvements giving you specific numbers (200, 400, 1000), it should be percentage based tied to number of population and other possible parameters.

Example: 

Manpower in system = amount of planets inhabited in system * amount of pop in planets * Garrison improvement percentage * 100

So the amount of pop in planets would reflect the number of planets that your empire inhabits and the garrison improvement would be a percentage multiplication. 

(System with 1 inhabited planet, 4 pop, no military garrison improvement)

400 = 1 * 4 * 0% (0% of 4 is 0, since it cannot be 0, its 1) * 100

So the 400 manpower comes from multiplying the number of inhabited planets, population amount, the percentage rate that the improvements gives you and 100.

Each improvement could stack into each other or not (balance issue that needs testing or more math). There could be other improvements that could take into account the number of planets in the system without it being inhabited (AI directed robot garrison installations in each planet)

(System with 3 planets, 4 pop,  no other improvement apart from the AI directed robot garrison improvement)

1200 = 3 * 4 * 0% * 100

(System with 3 planets, 10 pop, missile battery improvement and another t1 improvement (impenetrable bunkers) that give 50%))

= 3 * 10 * 50% (50% of 10 is 5) * 100

= 15,000 Manpower

This is consistent with the concept of system level pairing with the resource that gives you a garrison increase. It would apply the same but now % wise, always link with population level. The higher the population, the most populous the system, the more it creates revenue for the empire, so the more soldiers it has.

As you have noticed, my biased is toward having to siege and invade a system multiple times (most often will happen late game), thus giving time for the invaded empire time to muster fleets. It also serves to have chokehold systems as military bastions with all military garrison improvements built.

Obviously this would be a great Dust sink but isn't it a reality? To give a real life example, USA spends a big percentage of its GDP on its military (to mantain it) and that is why it is the only superpower in the world. 

It would also force the player make a choice:

• Have a standing army of fleets with very little investment in planetary defense or 
• Have military chokehold points that would give time to manufacture a big fleet.