Have you seen the troop model in Carrier Battles Mod? It uses infantry as small, cheap, high HP, low damage units and tanks as big, low hp, high damage units. The infantry are there to soak up damage, the tanks to absorb it. I'm sure something similar can be devised for SE5.
I think it's too quick to invade a planet. There should be a time limit as to how long the combat can go so that it can take several turns to effectively invade a planet. Plus there needs to be more militia seeing as how I land with 100 troops and all they can muster is a couple weak militia (this is on their homeworld.
Also, where are the anti ground troop weapons. There should be weapons to put on weapon platforms to repel invading troops. All in all I think using troops is a cheap tactic to gain territory very quickly seeing as how if you manage to land at all the planet is yours.
Perhaps your opponent should be building troops of his own? I mean, would you call it "cheap" if you attacked his systems and glassed his planets without issue because he had no ships to oppose you?
EDIT: and yes, I realize this is an AI issue in that case.
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Phoenix-D
I am not senile. I just talk to myself because the rest of you don't provide adequate conversation.
-Digger
I was going to suggest AI issues seeing as I don't PBW. It makes it kind of a deal breaker for me to buy the game if the AI can't build enough ships to fight me.
Also, the reports of 50 troops being contructed clutter the news.
I find that my ships refuel in enemy systems off of enemy resupply depots.
I still maintain that troops should be treated more like ships than fighters. The quantities of troops that can be easily landed on a planet brings my system to its knees, often causing the game to freeze, and is rarely necessary anyhow. I say make them cost ~3 times as much and weigh ~10 times as much. Giving weapon platforms the ability to hit ground troops at ranges and damages far exceeding them would also make things a lot more interesting.