Why does the AI still let you destroy their entire fleet, one at a time, while they are orbiting a planet? And then continue to build new ships one at a time and STILL let them stay in orbit alone to die.
I can understand that they're prioritizing defense first, but that's not how a human typically defends their worlds. When a huge enemy fleet (esp more than one!) shows up IN your territory, you don't just step up military production and garrison, you take your ships and form fleets to meet the enemy fleets. Crap, I actually have defensive fleets around at all times, helps on detection too. "Defensive offense" counter attacks is easily the best defense here but the AI still doesn't do it.
(Maybe) it makes sense to have one little ship defend each planet to stop the lone transports at least, but the AI would be MUCH more formidable if it counterattacked invading fleets with it's own fleets.