Bit of a topic drift but thus far (admittedly RC12) SO Aurora handles endgame fleets just fine. Soloing a 350k bounty isn't what makes something OP (and besides, that title goes to Doom which can solo even the Tesseract fights). The SO Aurora pretty much does everything I want it to do as my flagship for me to control the battle the way I want.
Obvious spoilers.
Currently my loadout is 4 antimatter SRM's, 3 minipulsers, 2 cryoblasters, and an ion pulser. Built-in are SO (I know, can't do it in latest version), hardened shields, and expanded missile racks. Also have expanded magazines, front shield, and solar shielding.
With skills, I basically have 4x9x1000 = 36k damage of alpha damage that I can lob on demand from the missiles. That's useful for forcing overloads/punching holes in armor, rescuing ships in trouble, or simply convenience -- remnant frigate teleported too far for my regular weapons? No problem, launch a volley and move on. Especially in early game when I'm getting one of the objective points.
The minipulsers with expanded magazines means 3x30x50 = 4500 kinetic damage to shields very quickly. They also handle fighters very well. The ion pulser is mostly for additional damage (was either that or pulse laser in the synergy slot) but it also contributes to anti-fighter.
The cryoblasters each basically do 3x the damage to hull as heavy blasters, at 2/3 the flux usage. In vanilla 0.9.1a, I basically relied on cobras since nothing else could do damage to capitals quickly enough. Nowadays, I just go up next to a radiant and unload with the cryoblasters; my carriers are relegated to broadsword/spark to help kill fighters.
The rest of the fleet is 4 SO medusas and 4 broadsword/spark drovers, until I find something better.
I've tried putting these weapons on tempest (and SO medusa) but I find it really needs to be on something like the Aurora for that overwhelming punch, since it has the weapon slots and the OP for it. Because of the high flux from SO, my limiting factor is really just the buildup of hard flux and my PPT. Soft flux drops away really fast. I haven't gotten the most updated version yet but without built-in SO it just means built-in something else with less OP to spend, likely getting rid of expanded magazines or something. At any rate it's a really fun build and it leads fleet battles just fine; I've done 4-radiant fights netting 4 mil XP (mostly because my small fleet gives me ~300-400% bonus XP, plus the story XP on top of that), though usually it's been 1-2-radiant fights for 2-3 mil XP.