Well that wasn't too fun.
I got the worst neighbors. While they weren't all purge-all-life behaviors, they were almost all xenophobes and they all hated me for many reasons. As I'm building up a fleet to vassalize one of the more hostile empires, I get a notification.
They had formed a federation. Every single empire surrounding my territory had formed a federation. And they all hated me.
It was only a couple months until the declaration of war. I would have been able to handle any one of them at any one time. Maybe even a couple at the same time from the same direction, but this was hell.
They all had warp and wormhole tech and completely surrounded me. My primary fleet was about 12k in power and was stationed near the territory of one of the weaker ones (and also was nearby the strongest enemy.)
The problem was the, well, geography? I had expanded in mostly one direction. One of the more moderate-sized empires was actually right next to my Capital, and had warp. I had planned on merging my fleets to have two primary fleets for defending the capital and attacking the upper front. That was probably my mistake.
So as I said, I had only expanded in one direction. Far out in the fringes of my territory, were the most powerful and weakest empires right next to each other. Adjacent to my capital, were two moderate sized empires. I had planned on using my main fleet to completely disable the weakest empire while using the secondary fleet to fend off attacks on my Capital.
The war started off well. I annihilated one of the empire's fleets in a single blow and had disabled most of their starbases. As I was preparing to start the invasion of one of their planets, the fleet from the strongest empire arrived - 20k power. I temporarily withdrew to merge more fleets into my main fleet.
After I withdrew, the empires next to my Capital started warping in fleets both at my Capital and at the bottom side of my fringe territory. Meaning I was effectively fighting a three front war. I decided to re-adapt my strategy. The secondary fleet would stay at the Capital while my primary fleet would split up to harass enemy minor fleets, troop transports, and infrastructure. Unfortunately this wasn't enough as the enemy gradually took my fringe worlds and started hammering at my Capital.
One particular battle at my Capital system left the secondary fleet crippled. I was forced to regroup my entire navy at my homeworld, hoping to at least hold out while I constructed some new ships. I left some minor fleets outside to continue harassing and take in the reinforcements from the remaining fringe starports. My empire ended when they ended up at my Homeworld with a fleet x2 the power of my Homeworld defense force.
You know, it's annoying to lose, but it is kind of similar to DF in the losing is fun category.